I would keep them at the normal pressure until you leave. Disconnect them from the CO2 and leave it at home when you go. By the time you get there and your beer is cold, you might have absorbed a bit of that CO2 but I bet it wouldn't be much. Attach one of these guys
http://morebeer.com/view_product/18306/ ... _Cartridge (I got one at my local HBS) and pour till it slows down. When that happens, give it a little blast and keep pouring. What I would do would be to use one and alternate from keg to keg. Remember to remove the quick-disconnect and the CO2 unit as one, otherwise you'll lose all your pressure.
Word of warning: be VERY careful not to give it a shot without the quick disconnect actually ON a keg. The pressure build up in one of those little plastic guys can blow it apart (according to first-hand experience from the guy at the HBS) and plastic shrapnel will be destined for your face.
Of course you could go on the safe side and just bring the tank, but that's just one more thing to lug around, right? If you did go w/ bringing the tank, I don't see why you wouldn't be able to add a little to each one as needed with that too.