My cat started at 10 and he does great.
I did begin with a month of camping in my driveway. Several times in that month he got p'd off at the whole van idea and left and slept in the yard for a night or two. This got me all worried that he wouldn't adapt, but uhe always came back to the van because he liked being with me.
When he stood in the doorway of the van and wouldn't let his best friend cat come in, then I knew he had really adopted the van as HIS terrirory :). But before that, seeing how much his bestie loved the van helped my cat see that it was something cool!
I have one of those harnesses that kitties can't escape from but he can. He is very cautious, though. When we camped at a place with bears and he wanted space, he crawled way up under the van and lay on the muffler. Safe, warm, and private! I did have a problem once when he liked a place too much and wouldn't come back to the van so we could leave :B
Moral of the story: Take your time and even an old cat may adapt just fine.
