First of all,it sounds like to me,that you have never stayed on Disney property before.Whether you have or have not,I mean no harm at all from my statement.Each resort on Disney property,has buses that run frequently all day and late in the evening.I allow myself to not be fully informed about this,but I will tell you what I know.
You can catch a bus at your resort at the designated area,and go to each park from your resort.You can also catch a bus that will take you to the Disney Marketplace,which is next to Pleasure Island,which is next to Downtown Disney.This is sort of the hub for going to different resorts.At the Marketplace,there is a designated area where you catch the buses to go to the many resorts.So to go to the Contemporary or Grand Floridian,I suggest to go to Marketplace from your resort and catch the proper bus for each resort and board that bus for the resort of your choosing.So if you went to Contemporary for dinner,you could catch the bus after eating,back to the Marketplace,and walk right over to Pleasure Island.Plus,there are three designated bus stops,one at Marketplace,one at Pleasure Island entrance, and one at Downtown Disney.These should be helpful in avoiding driving your car.Last year we stayed at the AllStar Sports Resort and once I parked my car,I didn't have to use it to go to the parks or Marketplace.I did,however,use it in the mornings to go to the McDonald's for breakfast which is located on Disney property about two tenths of a mile from the AllStar Resorts gated entrance.The only other time I used the car is when we left Disney property to go to Universal Studios and other places located off of Disney property.This was an enjoyable experience for us,even though the buses can get crowded with people standing in the aisles.But not on every bus ride.I hope I have helped you,but as I said,there may be other ways that I am not aware of.