Here's another idea. If you remove the SD cards and update them via iFly Connect on your PC, it looks like you could simply copy either the whole #FlightPlans folder to your SD cards, or just the individual .ifp file that has the RealPlan constructed route(s). That would give you the utility of RealPlan, plotted on your desktop and flown with your 740, until an iFly760 is introduced, if it is.
It seems the 740 simply doesn't have the capability to efficiently run RealPlan. This means that either we don't use RealPlan on our 740's, or we transfer flight plans from the PC to the 740, either through the sharing capability, or as I described above.