My advise from our experience:
R-Day: Stay at The Thayer if you can. There is usually a long waiting list that if for some reason you don't go, there will be someone who will want your room. Plus, when you get access to prospective-net, you can post on there that you have a room available and I'm sure someone will snatch it up. The Thayer is expensive and they sure do jack the rates up for these special dates, but boy is it worth it for R-day. There is so much stress that day. We didn't want the added stress of getting caught in traffic, or the car breaking down or an accident or a myriad of other things that are out of your control that could delay you getting to Ike Hall at your appointed time. From The Thayer, there is a bus you can catch or it is a nice walk. Also, you can get a full breakfast there instead of the 'cereal, toast and juice bar' at some of the other hotels. It was stressed to us that the Cadet Candidates get a good hearty breakfast b/c it was going to be a long and stressful day. Don't add hunger to the equation. It was fun to look around the dining room at breakfast and see all of the other CC's and their families.
A-Day: Last year, the Cadets (after they were released) could go off-post with you to your hotel. You couldn't stop anywhere along the way and eat, you had to go directly to the hotel. The Cadets could eat in the hotel dining area but had to be in uniform. Therefore, it didn't really matter where you stayed. We stayed at the Homewood Suites at Stewart because we could get a suite and it had a little kitchen. I made brownies for him there! He could go in the bedroom and take a nap while the rest of us could be in the living area, watch TV and make brownies without disturbing him. I think he had to be back at 1am. The rules may be different this year as far as what kind of off-post privileges they get, so I would wait and make hotel reservations once you know the rules. IOW, I don't think that is it as necessary to fork out the big $$ for The Thayer on A-day. But if it is in your budget, The Thayer is the place to stay. You can't beat the convenience! And no, I don't have a vested interest in The Thayer - just an opinion!