You really can't sync the iPad to more than one iTunes. Apple has designed it so that it's pretty much "one iTunes, one iDevice." Yes, that's not the greatest way to do it, but it is Apple's way. It is a long, complicated and involved process just to transfer to a new computer, with risk of losing your "stuff." It would be difficult to continue to do that transfer process on a regular basis.
So, my suggestion is to just use one computer.
Marilyn