I know that FPs in DCA and DLR are disconnected, so you can get one at DLR and then hop over and immediately get another one at DCA. However, in order to do this, you'd need to go through the park entry lines twice - once to get to the other park and pick up the FPs, then again to rejoin the rest of your party in the original park. Then when you go to actually redeem those FPs with your whole party, you have to hop back and forth AGAIN.... I just can't imagine this taking less time than sticking with the FPs in one park.
Does anyone know if this actually works to save time? Is there a way to estimate the entry line time based on the crowd calendar?