The RAC counter is open from 5-1. The rule is that your bags must be checked in, completely, your boarding passes in hand, no less than 3 hrs prior o flight departure. If you arrive at the RAC counter less than 3 hrs. 15 mins prior to flight time, you won't be able to check your bags. It takes at least 10 mins to get checked in, and bags tagged.
As far as the 2.5 hrs prior to flight p/u time goes, that's a first for me. It usually isn't take more than half an hour to get on the highway, even if you are the first of several stops...that would get you to MCO 90 mins rigor to flight time. That's okay but could be cutting it close if security is crazy. I think I would have asked them for an earlier p/u, but that's just me.
When I check out, I always take my bags down to the RAC counter as early as possible. Then I don't have to worry about it. People get DME and RAC confused all the time. Yes, Disney 'says' they are the same, but they aren't, not really. Anyone can use RAC, as long as they are flying on one of those participating airlines, and they are staying at that resort. You can be driving back to the airport, or taking a town car. No need to be riding the DME bus back to MCO.