There are times when I'd really like to have all my Mac-local folders (Mail Library) on my iPad. I'm not even sure of the way to do that. Is that an option in iTunes during syncing (I'm not at my Mac right now)? Would the size of my Mail Library require/take up the same memory on the iPad? If so, what are the options to minimize the amount of space needed?

My suggestion would be to move over to an IMAP email service and then move all the email folders and emails stored on you Mac over to the IMAP server. With an IMAP email service all of the emails are stored on the server and devices are able to all access all the same emails.

A recent Macworld article on this subject might be useful to you.

How to convert a POP email account to IMAP | Macworld (http://www.macworld.com/article/1165600/how_to_convert_a_pop_email_account_to_imap.html)

I did switch over to IMAP last year but haven't yet moved any folders over since I do like having access to all my emails without a network. That might have to change I guess.

IMAP allows this. You keep a local copy that is a mirror of the copy that's on the email server.

That's new to me. How do I set it up to mirror a copy? I'm using gmail mind you.

On Gmail, each of your labels will automatically appear as "folders" when accessing your mail via iMAP. You can also go into your "Labels" settings and choose which of your labels you want to appear as IMAP folders.

Keep in mind that the iOS Mail app will only automatically download the INBOX folder, so you still won't get a full "sync" of your mail onto your device in the background. Other folders will download as you open them -- up to the last 25 or 50 messages according to your iOS Mail settings -- and mail will be kept on the device once downloaded, but again this will not sync automatically in the background when using IMAP, so your mail will only be current as of the last time you opened a folder while connected to the Internet via Wi-Fi or cellular data.

As an alternative, since you're using Gmail you may want to take a look at setting up your iPad to use Google Sync instead of IMAP (see Google Sync for your phone (http://www.google.com/mobile/sync/) for more information). This basically uses the iOS Exchange ActiveSync support and provides you wish push e-mail as well as the ability to sync multiple folders/labels in the background (also via push). It can also be used to sync your Google Calendar and Contacts. With Google Sync, any folders you've selected for push synchronization (in the iOS Exchange account settings) will automatically be synchronized and kept up to date in the background regardless of when you last opened them.

After watching their video, I can't see how Google Sync is geared toward what I want. It looks like it only deals with web-based email.
I just went to my web-based Gmail account and don't see any import options. Maybe I didn't look deep enough. To get my local folders into Gmail, will I have to export/import them as mbox files?

After a bit of searching, it looks like I'm supposed to be able to drag and drop any of my Mail folders into my Gmail account. I just tried that and it doesn't import.

Okay. I just created a new folder in one of my Gmail accounts and dragged the local emails of the corresponding folder to the newly created one. They went over okay but now they're not in my local folder.

I think you're going about it in the wrong direction... You can't "import" Mail into the iOS Mail app like you can with the OS X Mail app. The only way to get mail into the Mail app on IOS is to download it from a server -- either POP3 to a local, device-only folder, or synchronized with a server folder via IMAP or Exchange.

Google Sync is Exchange ActiveSync. I've never watched the video, so I can't be sure what that's actually trying to say, but the bottom line is that you're basically setting up access to your Gmail account as if it were on a Microsoft Exchange server -- you go into your iOS Mail settings and add it as an "Exchange" account. At that point you get push e-mail and can also choose which Gmail labels/folders to have pushed to your device so that they stay in sync with the mail on your Gmail server. Click on the instructions for setting it up on your iPhone for more information (the same basic instructions also apply to the iPad), or simply go to this link: Setting up Google Sync with your iOS device - Google Mobile Help (http://support.google.com/mobile/bin/answer.py?hl=en&topic=14252&answer=138740)

If you have mail in local folders on your Mac, you will need to upload those to Gmail via IMAP using something like the OS X Mail app -- simply drag-and-drop the messages from your local folders into the equivalent Gmail folders (which are actually Gmail "labels"). If the corresponding labels/folders don't exist in your Gmail account, you either need to create the labels through the Gmail web interface or you need to create them as "folders" via the OS X Mail app.

Okay. I just created a new folder in one of my Gmail accounts and dragged the local emails of the corresponding folder to the newly created one. They went over okay but now they're not in my local folder.

They won't be in your local folder any more unless you copied them rather than moving them. However, there's no need to keep a "local" copy -- Mail will do this for you. The folder is synchronized with Gmail via IMAP, so every message continues to exist as an offline accessible copy on your Mac as well as in your Gmail account.

If you want to keep your original local folders as a backup, you can copy the messages to Gmail by holding down the OPT key while dragging and dropping. However, this will result in you having duplicate messages -- one in your Gmail account and one in your local Mail folder, which will be a pain for doing things like Spotlight searches. As an alternative, you can simply rely on a Time Machine backup or other form of backup of your ~/Library/Mail folder before you begin, or use the "Archive" feature in Mail to export all of your local folders to standalone archive files.

If you have mail in local folders on your Mac, you will need to upload those to Gmail via IMAP using something like the OS X Mail app -- simply drag-and-drop the messages from your local folders into the equivalent Gmail folders (which are actually Gmail "labels"). If the corresponding labels/folders don't exist in your Gmail account, you either need to create the labels through the Gmail web interface or you need to create them as "folders" via the OS X Mail app.

I believe this is the only part of your post that applies to me. With IMAP, I'm already seeing the email in my Gmail account on my iPad. It's the local folders/emails on my MBP in Mail that I want to get into my Gmail account so that my iPad can see all of them.

I have created a folder in my Gmail account and dragged the local emails over, but now they're gone in my local folder. How can I keep my local emails while at the same time have them in Gmail so that my iPad can access them, or am I asking for the impossible?

****I just found how to do that...I right-click-Copy To... (my created folder in Gmail) and bingo- showing up in both places now. I guess I answered my own question. I tend to do that a lot.

As I noted above, I wouldn't recommend copying them into your Gmail folder as you're basically keeping two copies on your computer. The Gmail folders are still synchronized as "local" copies so there's no need to also keep your messages in your local folders. If you do, then searching via Spotlight on your Mac will always yield duplicate results for every hit -- one from the Gmail folder and one from the local folder.

With regard to seeing the local messages on your iOS device, the point I was trying to make earlier about IMAP vs Google Sync is that you won't get these folders synchronized automatically in the background -- they only get downloaded when you open the folders. This is fine if you always have online access, but if you're trying to cache for offline use, there's a good chance you'll find an important message missing when you actually go looking for it because it hasn't actually been downloaded yet. Further, the iOS Spotlight feature won't find new messages on the server unless they're in your Inbox or unless you manually go into the Mail app and visit the appropriate folders individually to update them.

With Google Sync (Exchange ActiveSync), you can have specific folders configured to be automatically pushed to your device, which means they will be updated in the background which will ensure that new messages in those folders are available for offline use regardless of when you last opened the folder.