ScarletIndigo, I do believe the resorts provide a transportation map on how to get around using the WDW transportation. In addition, I believe resort phones may even have a 'transportation' button...or at least they have someone at the desks who can answer your questions.
I do agree that WDW transportation is good but I find that my own car is quite convenient when going to eat at the various resorts for dinner. Being that transporation from resort to resort is virtually non-existent, it can take an hour or longer at times to get back to our resort.....and I find that to be a hassle and a waste of time. In addition, many times of the year the parks close early so your only option to get back to your resort will be to go to DD. We have taken cabs in the past and they are pretty effecient but cost. Being we generally drive to WDW anyway, driving to the resorts for dinner is a convenient option.
Again,WDW transportation is very good, but there are times when a car is a great convenience. Is it worth renting a car? To me, that would depend on how many different resorts you were planning to visit in the evening and how much you value your time.