I have been to WDW only a few times but know the place inside and out through research. I went to DLR for the first time in August, only did the one day park hopper, but I think I can help.
First, it's good that you're spending three days at the park as you will see everything. But my first tip is to absolutely get the MaxPass, especially if you want to get as many rides done as possible. It will save you more time than you can ever imagine and would highly recommend it.
At DL, rope drop Space Mountain and go from there. Note that Space Mountain has a single rider line that is rarely used, when I was there in August the ride had an 80 minute wait but walked on as a single rider! It's great for rerides, but if you don't want to rope drop Space than rope drop Matterhorn.
For DCA, rope drop Mission Breakout. I know it goes against all touring plans, but if you go to Guardians at opening and walk on, you can easily get out and get a FP for RSR. This is made much easier with MaxPass as you can book a RSR FP while waiting for the rope to drop!
As WDW vets, do TSMM once cause it's a fun ride, but don't make it a priority. Also don't worry about Soarin' as it's an exact clone of Epcot's, if you haven't done Around the World yet, then I'd do it once. Don't worry about Star Tours at DL as it's an exact clone of DHS's. Otherwise, still do all the rides in DL that are like MK such as BTMR, Splash, Buzz, etc., as the rides there are different though they share the same name!
I really hope this helps!