On the Mac, you can easily create m4a files for all SGU files in a folder.
If using version 2012.5 or higher:
This is done by the menu option (File- Batch Save all Songs in current folder to '.m4a). Version 2012.5 or higher required for that batch function. So to use that, load in a song from the folder that you want, and then it will be the current folder, and then do that command.
If using version 2012, you can only make one .m4a file at a time (File- Save Song as .m4a ) ). If doing that on a bunch of files, you need to load them in one by one, and then choose that menu option (since the batch file feature was introduced in version 2012.5)
Once you have the folder with .m4a and sgu/mgu BiaB songs, you just make a zip of the all of the files, and you will send this .zip to your iPad.
It is not needed to setup some kind of temp network as jodroog suggested. You just need to be on the same wifi network.
Watch the video that shows you how to do it (click on "Downloading Songs from your Mac"http://www.pgmusic.com/support.iphone.mac.htm
Here's a direct link