Another vote for Rivendell. You can get a nice build for ~$3,500 from them. Also, you say you have no "access" to Marin, but you can certainly order them online. The Four Corners sounds about perfect for you.
If you want to spend less then Rivendell, lots of companies sell adventurous steel touring bikes that might be perfect:
https://www.rei.com/product/122462/c...B&gclsrc=aw.ds
https://www.citygrounds.com/products...gaAn5eEALw_wcB
https://www.crimsonbikes.com/product...IaAp-HEALw_wcB
https://mybikeshop.com/products/2021...0aAvp5EALw_wcB
https://surlybikes.com/bikes/ogre
https://www.crimsonbikes.com/product...kaAjrGEALw_wcB
..etc.