One potential option is the "Katy Trail", a 237 mile rail to trail, that starts near St. Charles, Missouri and heads west along the Missouri river across a large portion of the state, ending in Clinton. I have bicycled a lengthy stretch of the...
Ron "Butch" Briery wrote the first guide to the California Mission Walk. He lives locally to me, and has walked a few Caminos too.
https://missionwalk.org/the-hikers-guidebook-second-edition/
Cicerone has a guide regarding California Mission Trail. To be honest I have not read this seeing as I am not planning this trail, but would be curious to see what it has to say. Good luck whatever ever path you take.
Here in the US there are a number of potential longish treks along features such as historic canals, but they are mostly used for day hikes, sometimes for several days, but accommodation is mostly motels in towns (some very interesting and...
I am also following Dave's trek across America. He is off the ADT now and following the Oregon Trail which is not an official trail. I highly recommend following Dave...
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