I've been to ACC only once but to AHA many times.
What I'd recommend is to get an official hotel list and find out the routes of the buses. Lay it out on a map if there is one or make one. Usually they have shuttles that take you back and forth to the convention center if you are not in walking distance. Once you get the routes, go to hotels.com or your hotel search engine of choice that allows you to look for those dates you want but addresses close to whatever address you want to search by ie. the convention center or a hotel on a nearby route you can walk to. Usually in the past if you had your badge, you could hop onto the shuttle and get there. I would try to avoid going to hotel that is too far out if you can avoid it as it is nice to be able to rest and or drop off stuff.
If you look now, you should be able to find hotels close to the "official" hotels but still on the route. An attending I knew did this all the time.
They do have a fellows in training track of information.
What I do recommend is to look carefully at the program brochure on line or the mailed one to see what you would be interested in seeing. Make a loose schedule. There is always a crazy amount going on and it is hard to do it all. Also, the meetings are often captured on CD or DVD if you want options to get info later.
Planning the meeting helps so you can leave time to see things that you might not be able to catch later like poster sessions, and networking.
I can't remember if you had an interventional interest but that meeting also tends to run concurrently with ACC.
I don't necessarily recommend this option to everyone because it does require work and you may not necessarily know what you'll get. A friend of mine has been able to secure cheap housing previously by finding folks to sublet apartments and such on craigslist. We did this once on a trip to New York for two weeks. The guy went out of town and we rented the place for two weeks. It does require some time to look to see what might be safe, reasonable etc.
I hope this helps. I hope you enjoy the meeting.
Good luck.