My shortest trip, from deplaning to resort checkin, was 45 mins. That was with a towncar service and only carryon luggage. The longest was 85 mins, using DME and being the last of three stops with huge amounts of luggage to be disbursed at the first two stops.
My average time, 5 trips at least with DME, is about 70 mins.
Here is a breakdown, as best as I can remember, of the different times I have had...
1. DME....50-85 mins, most around 65 mins
2. Towncar...no checked luggage, only carryon, 45 mins
3. Towncar...with checked bags, 55-70 mins, depending on time at baggage claim.
4. Mears shuttle...last Sept, so not the 'old' Mears shuttle...75 mins.
Just so that everyone is on the same page.....being able to check your luggage at your resort, for your return trip, and get your boarding passes, has nothing to do with DME. It is RAC...remote airline checkin...and is available to anyone who is flying home on an airline that participates in the RAC program at WDW. You could take the DME bus back to MCO, or you could go back in a towncar, or in a rental car...you can still use RAC if you are on the right airline.