We did two days at IOA/Universal with the 2 day/2 park ticket with transporation from WDW 8/30 & 8/31/11. The tickets DO ALLOW you early entry. We were in line waiting for the 9 am opening, and I went to get a park map and saw the "early entry" entrance. I went up to the ticket checker, showed her my ticket and asked if I could get in early with the ticket, and the answer was YES!! Called my son over and we were in at 8:15am.
The Mears transporation was fine as well. We arranged for Mears to pick us up from POP Century at 7:25am both days. On the second day, they had booked 13 people for a 11 person van. Because of the different family sizes waiting, my son and I decided to let everyone else go. The Mears driver simply called over a waiting taxi-van and we had our own personal transporation. Return trips were no problem.