We love the AutoTrain, and have taken it many times. However, it is not a pet-friendly route, so only service animals are allowed. The Amtrak pet policy is found here. In all my trips, I've also only seen one service animal on the train, since there is only one stop (around midnight), so it isn't a pet-friendly route.

If you decide to try it, without the cats, it is a decent trip, and it is nice to have your car (and everything you can pack in it) while in Florida. We pay extra for the sleeper car, it is nice to have a quiet room, and an actual "bed", so we can get at least a few hours sleep on the train.

There is an option for "priority offloading" which guarantees that your car will be one of the first 30 off the train, which can save a lot of time at the arrival. For departure, you can arrive as early as 11:30am or so, but you don't have to be there until 2:30pm, so if you don't care about your meal time (you can select a 5, 7 or 9pm dinner once you check-in), there isn't really any advantage to getting to the station early.

We've had some quick trips, where we have arrived super early, and some where we have been hours late ... all depends on the traffic on the tracks (and the time we hit a fallen tree!). Still, a great option to driving the whole way.