Your selected route is fine. 29 is four lane and 86 is a good road. We drove 86 down to Durham in our previous 36' DP several times and it was fine.
Most all of the roads that will take you from Lynchburg over to Natural Bridge are somewhat curvy but nothing that would be a problem. 501 is as good as any of them. Take your time and enjoy the view.
220 all the way to Roanoke and then I-81 would seem to be taking you a long way around. And, much of 220 between Bassett and Rocky Mount is up and down and twisty too.
'07 Country Coach Allure 470 Siskiyou Summit #31578, Cummins ISL 425; 2014 Ford F150 toad; Air Force One Toad Brake.
Glen Allen, VA; Smith Mountain Lake, VA.