>>2306529Eastern MO is great for /out/. There's a ton of fantastic trails and views within an hour's drive; check out the area around Farmington and Ironton. Taum Sauk Mtn State Park, Johnson's Shut-ins SP, Buford Mtn Conservation Area, Elephant Rocks SP (really cool), Bell Mountain Wilderness, the Ozark trail, etc. Land is also much cheaper than Colorado. The Ozarks in southeastern Missouri have some of the cheapest land in the country if you buy in bulk, rivaled only by Arkansas and West Virginia.
As you suspect, Colorado is full. You can buy some cheap scrubland there, but nothing primo. That state is Californicated and will only become moreso as the years roll on. St. Louis is an underappreciated /out/ city actually, you've got thousands of acres of National Forest within an hour or two. You can also drive two hours down to the Shawnee National Forest in Illinois, which has its own neat spots.
Does any of it match the grandeur of proper mountains? No, it doesn't. But it's cheap, not crowded, and what nature they do have is pretty kino in its own right. Spring and fall in the Ozarks are absolute bliss when it's not storming. Just bellisimo. Can't think of many places I'd rather be in those two seasons.