There's already an effort to do this in various places. Look up East Coast Greenway for an example.
FWIW - I have little interest in this kind of stuff. Yes, I'd use sections if they ran where I wanted to go, But I've spent so many years riding "blue highways" and have no issue with shared use roads.
exclusive bike/pedestrian trails are nice, but will never have the network density of the existing secondary road system. So, even if we have trals, a decnt amount of touring will be on shared roads.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.