FWIW, the gym at the hotel has free weights and a few cardio machines. That said, I totally get wanting a more thorough workout experience.

As for a car, if you get the 145, you may go straight through, sims and all, in DFW. A car might make sense then. If you're 175, definitely wait till AFTER Indoc as you're likely to have a very long break. Even then, you're not in town THAT long, because you go to St. Louis for sims. A couple folks in our class had cars and they used them some, but they generally still took the group shuttle to the training center. I walked to Wal Mart (a "neighborhood market" variant), and took the hotel van to other places. I did give some gas $$ to catch a ride with the car folks a couple of times, but could've gotten along just fine even if no one had a car. And yes, plenty of Uber options!

One minor thing-- getting an uber from the training center to the airport is simply impossible (the app assumes you're at the airport and makes you pick a terminal for the pickup...)! So if you don't have a car and are trying to fly home during a break (the wisdom of which varies per the situation), be prepared to go back to the hotel on the training center shuttle, and to then take a hotel van to the airport. More info than a new hire probably needs in advance, but it did affect several of us, requiring a bit of planning.