Possibly niche it more toward motorcycles. Allow options to chose saddle time or daily miles and/or road type on google maps. Input points of interest you want to see and let it show routes with daily miles, gas stops, and hotels/camping along the way. That would be the best to just simplify trip planning.
Work with advertisers and sponsors, like Best Western-who has been working at becoming a "bike friendly" hotel chain. Live links to local information pages, ect.
Use google maps as a platform and utilize the layers for maps, satellite view, and topographic with printable pages.
These days, you have to have something that will work on Android or iphone. Set it up to automatically save data to the phone in low cell signal areas so the user hardly notices it in a canyon somewhere. Save contacts (hotel numbers, AMA service, etc) in a easy to use interface. Then you'll be getting somewhere.
When we leave a place a part of it goes with us and a part of us remains