We tried RP once a couple years ago and had a massive fail. We were staying at Poly and RPing Epcot to do the Tier 1 rides. It all started with the insanely long security line at TTC. After we finally got through that, I remember having to wait for monorail. Finally made it to Epcot and then had to wait in another insanely long security line there too! Needless to say, we didn't make it on any Tier 1 rides that morning.
Just this past weekend, we tried the EMH at HS. It was from 8-9am. We were staying at GF, so we took a bus over and we timed it perfectly and pulled into HS bus area at 7:46. Problem is where the bus lets us off and walking all the way to entrance we lost some time, but we still made it into the park by 7:59 after security line. We practically ran back to SDD and saw it was a posted 120 minute wait. We got in the line that snaked around 3 times before the ramp right at the 120 minute sign. I timed it from that point until we were getting on ride and it took 62 minutes. Would we do it again?? No way.
We just can't seem to time mornings right.
I think we'll stick to what works best for us, and that is starting our FP's right around 11am. Gives us time to sleep in a bit, grab some breakfast at the resort, and casually get to our park.