Here's my advice (not that you need to hear me blab about the gym any more):
If you go the week after Thanksgiving, go at the times you plan on going once you have classes. You should know what your body feels like at those times.
If you do decide to sign up for a month, take that Personal Training Session, definitely. I was foolish for not taking mine when I first started going to the gym - while I stubbornly needed some time to just get used to going, I also feel like I wasted at least a few months doing a plan that wasn't necessarily doing much for me. Plus, with your recent injuries, regardless of rehabilitation, your trainer will (hopefully) steer you away from exercises that may cause undue strain.
Ubertuber is right about the 24-hour thing. Unless you plan on working out after 11 PM or before 5 AM, it's really not that great. But I think the benefit of it being close to home is a great one.
OTK is right about the workout planner. Not only will it keep you on track, but it will let you follow your progress and see improvements.
I'm wishing you all the best with this. Honestly, just saying you're going to do it - to all of us - is a step in the right direction. I know you can do it - and once your body gets used to all the changes that going will bring, I bet you'll feel really good.
