We would get in late on Friday night and stay at Coronado ($191), then start at Epcot on Saturday. We'd likely just pack an overnight bag and have everything back into the car that morning to drive to Epcot and then drive over to the Grand Floridian mid-day (we only plan to spend a few hours in Epcot). GF is $856 total for two nights.
We'd likely park hop to Animal for Saturday afternoon and possibly Hollywood for the evening (we did four parks in one day last time we were there!).
We'd then start the day on Sunday at Magic - walking or monorail from GF. We'd be able to hang out and relax on Monday as we're not doing the parks that day and leave in the early afternoon.
Both girls really want to do GF, so I think that's what we'll end up doing...
With no kids and very little luggage - and not having to rely on bell services to deliver, I think we can make it work. I've done a split stay before and didn't love it, but GF isn't available all three nights, so this is the only way we can stay there.