We did travel with a cat for a summer and at 20 years old he was content to sit still for the entire ride. He could have endured a train ride. The dogs would be a handful and one would be howling at every horn blow.
Well, since this thread has resurfaced, I'll affirm what Guest said above several months ago. My two six-year-old cats traveled excellently by automobile from Philadelphia to Lynchburg to Las Vegas, and back so far to Lynchburg. Quiet, polite passengers. They were fine for ten hours at a stretch in small carriers between hotel rooms (which is to say, ten hours at a stretch without food, water, or litter) several days in a row. I gave them the option to wander around in the car, but after a quick exploration they settled back into their carriers with their security blankets. (Well, actually, despite the smallness of the carriers, both cats preferred to cuddle together in one!) Cats are very sturdy, relatively not-needy creatures.
I would feel totally comfortable, based on this experience, letting them travel just like this Philadelphia to Lynchburg in an HVAC baggage.
Along the way, my cats saw their first Amtrak train, the Southwest Chief at Winslow:
And got their first ride on the rails, on Fort Smith Light & Traction car #224 (Fort Smith, Arkansas):
Horn blows are nothing compared to the noise of a vintage 1919 trolley on bumpy track! And they seemed totally content to look at the scenery, the motorman, and the conductor the whole ride
The conductor said he'd never had cats as passengers before, but was very happy to take them aboard.
They've become railfans:
And they got to meet Smoky, the cat who lives in Frisco #4003 (with her caretaker, docent of the Fort Smith Trolley Museum Dr. Martin):
Ok, I'll stop with the cat photos before y'all get catty