MEARS contracts with Hilton and they run a nice bus with a regular schedule and it’s a loop to all four parks and Disney springs. Yes, you are dropped off at the gates foe every park with the exception of MK (you’re correct, you go to the TTC).
However, we end up using Uber/Lyft quite a bit because it’s not terribly expensive and you don’t have to make unnecessary stops.
Depending on what park you’re going to, I would use the bus if it’s early in the loop and Uber/Lyft if it’s not.