Back road road trips

I want to plan a road trip across country not using I-90, I-40, I-80, a scenic route. When I put in no highways, no tool roads, no ferry I get an error “We could not calculate your plan

No working plan could be found. Please check your settings, for example, adding additional charger types would greatly increase your chances of getting a plan - if the problem remains, you may use the button below to report an issue to us.”