It's actually easy and very convenient! All you do is cross the street (so yes, you will have to wait at the crosswalk for the light to turn) and follow the path that takes you directly to the GCH main hotel entry. Once in the GCH, you either go to the left (follow signs to DL/DTD) or go straight through the lobby, following signs to the "Guests only" private GCH entrance which puts you into DCA right in front of GRR. Anyone staying at one of the 3 Disney properties can use this entrance, just make sure you shown your room key. We've done the walk to DCA in 5 minutes before from PPH. DL is a bit longer, 10 or so minutes, but the walk is pretty. Once you cut through the GCH, you enter DTD about 1/2 way down, so not far to walk to DL and it's very pleasant, especially in the morning when things are quiet and just waking up!! We love staying at the PPH!!
Whatever you do, I would not reccommend the route that is marked out at the PPH to get to the parks. It has you exit out the back of the hotel and take a path down towards the DLH and it means you have to walk all through DTD, and it takes much longer. Definitely use the GCH shortcuts to cut time.