Ditto on Gary's suggestion of I81 to I77 to I26 to I95 if you're going to Jacksonville or further south. The Baltimore tunnel is the only one I know of that won't allow propane and you'd miss that with the foregoing route.
--2005 F350 Superduty Crewcab, 6.0, 4wd, short bed, 3.73 gears
--2016 Montana 3711FL, 40'
--SOLD 2014 Wildcat 327CK, 38'