Hi! I have lurked here for awhile. Don't post much. We are driving from Des Moines, IA the end of May. Have never driven to Disney before only flew. Planning two days down and two days back. A little worried about 20 hours on the road but also excited.
Two days down for 20 hours is eminently doable, if I understood you correctly. Actually, one tip I have picked up after trying it on my second drive down from OK was to make the
first day a bit longer when you split up the drive. For us, central OK to WDW is a 20-hour drive, too, but I don't split it up 10-and-10. I push our first day to 14 hours - really the max I'm comfortable pushing a single day - which leaves me only 6 hours the next day, getting us into WDW proper a few hours early and not leaving you anywhere
near as fatigued after that second-day drive.
We followed this strategy the last three trips and its really worked out nice for us; although in 2011 our early arrival was botched because WDW's computers were being overhauled *the day we arrived* and *everyone's* check in was being delayed - it took us *four hours* to get our room, scuttling our plans to spend our first afternoon in Downtown Disney
. But we were comped for the first night, fortunately. But that's an aside. The point here is that splitting the drive heavy on the first day was a bonus on the second day.
For your route, it appears that Nashville is a down-the-middle split 10/10. If you pushed the first day two more hours to Chattanooga, you'd only have an 8-hour drive the next day; if you pushed it just a tad further, to Marietta, GA, that's about 13-1/2 hours, leaving only 6-1/2 the next day. Might be worth considering!