Hi Beth, sounds like a fun trip and good idea to plan ahead.
A couple of comments.
1.With 5 of you, no matter how nice the hotel, you will be in a cramped room at Disney unless you look at one of the home away from home resorts that has 1 and 2 bedroom units. These are at Boardwalk, Old Key West, and I think that the Beach Club may have some suites. These will be very expensive, (300-500 a night) but if hubby's account will let you do it, go for it.
No matter where you stay on site, there will be at least a 15 minute trip to the convention center on International Drive and no trans other than a cab, or you drop off.
2. I know you are set on wanting on site accomodations and if the budget will stand it go for the 1 or 2 bedroom units above.
I have known so many folks who stayed in a Disney room at $125 to $300 a night and went nuts after a week crammed together. Before you decide "on site" for sure, check out the posts here about homes and condos for a week. Imagine a two or 3 bedroom luxury unit, with pvt bath for mom and dad and lots of room for the kids. Add a big pool and just a short 10 minute drive to Disney and it can make for a fun week.
I guarantee you if you stay in a Disney resort that is not on the monorail (Polynesian, Grand Floridian, and Contemporary) and rely on Disney buses it will take 3 to 4 times longer to get from park to hotel than driving from Disney parking lots to your home or condo.
3.Be sure to check the ticket offers for convention goers if you stay at Disney. There is a special deal that will give a 2,3,4,5, or 6 day hopper just for the time you are in town and give you a little break on price but free admission to Quest. They are a good deal because they offer 2 and 3 day Hopper passed not available to the public.
4 Good Luck and keep asking questions.
Grandpa Ted