I have stayed at the Best Western Plaza on IDrive and used their free transportation to WDW. This was back in October 1997.
I found the service OK. It dropped you at the Ticket and Transportation Centre near MK, where you could catch the monorail to MK or Epcot, the boat to MK or busses to AK or MGM.
The downside is that you are fixed to the bus timetable and return busses at the end of the day are crowded, or return too early to enjoy the nightime parades etc. So you may need to budget for a taxi to get home.