From the passenger standpoint things should pretty much be back to normal. The replacement cars (to replace the damaged trainset) are almost identical to the regular Auto-Train cars, with the exception of the lounge and all-deluxe sleeping cars. They ride just the same as AT's regular cars, are just as comfortable, etc. Also, only one (of two) Auto-Train consists was damaged, so you may be traveling on the standard train anyway. The only issue I can think of would be if all the deluxe sleeper space had (well in advance) been sold out and some passengers were bumped to standard sleeper (AT is running short one deluxe sleeper), and Amtrak would have already addressed that issue with affected patrons. Some cars from the derailed train are apparently already back in service (auto-carrier cars and both locomotives).
Auto-Train often attains (or ties) first place on on-time performance among all long-distance trains in the Amtrak system. In the last few days, one train was about (I'm recalling from memory) 20 minutes early, another 15 minutes late. But, since automobiles have to be unloaded before anyone can leave, the difference in time is insignificant. Cars are not unloaded in any particular order; you could be on a late train and still have your car by 9:00 a.m., or an early train and not have it until 9:30 or later. Last time I was onboard, I had one of the last cars off and that was still only about 45 minutes after arrival.
From Amtrak's standpoint, things are hardly normal. The replacement cars were rounded up quickly by robbing the Washington D.C. - Chicago train (the Cardinal) of it's Superliner passenger cars; that train became low-level using sleepers taken off a Boston-Virginia train. Auto-Train will see more of it's equipment return in the weeks and months ahead, and everything will proceed as usual.