On the MM days when there is only early admission at DL, and a rope drop in DCA you can go strait to RSR with nobody already in line. This works only so-so.
There is a rush to RSR, it's been like everyone in the park is going to the same place, so not easy to be first. Literally you can be first in the park, the first person at the rope but when you get to RSR so many people get past you, you get a 30 minute wait.
One tip which I've done and it works semi well is to stay to the right as you are being led into CL. When the rope is dropped in CL, the CMs let the people to the right free first giving them an advantage. What I mean by semi well, is this causes the crowd to shift to the right and people slip into the right from the left. So being on the right has advantage but it's not a guarentee of a shorter wait.
The worse part is that the real question is will RSR be open? I've tried this and it's been 50-50. However a couple times I got on RSR early enough, that after I went on the ride after I went strait down Route 66 and got a RSR FP.