Ben, I tend to agree with 4 Feline House.

Wether a cat is an indoor or outdoor cat is not really an important factor in your situation. The thing to remember is that cats like stability, they like to know their surroundings and will start feeling very uncomfortable in new environments.

I love the outdoors myself but I would never even contemplate taking my cats with me on an outdoor excursion. They would hate it and I would probably never see them again...

Have you ever been holding a full-grown cat on a leash when it panics? Take a full medical kit with you just in case - this is no joke. You have to either hold on tight and try and subdue you cat or let him/her go. Either way one of you is going to be very emotionally disturbed.

I suggest you execute your plan with great care, good luck