Mountain bikes are no joke. I still have my original 1997 Cannondale F500 (that I still am using to ride trails). People thought I was nuts to pay $1k for it back then. I'm getting back into the hobby and my buddies' mountain bikes are over $7k! They have like 3 different bikes for every type of terrain (snow, little rocks, big F-ing rocks). Full carbon, full suspension, wicked pivot this, rad travel that. I just ride a hardtail but when someone says 'bike the country' this is how I see it. Just other options. You can get super cushy mountain bikes but hardtails are bare minimum and Spartan. Light and agile; the rear suspensions are your knees, back and butt. Stupid fun on the downhill sections.
My hardtail. The only thing more hardcore is to take a mountain bike (zero suspension) or cruiser and believe me people do. I always give them OG's a nod because that is straight up crazy.
I love me some gasoline powered dirt bikes! If I had the mojo to do that today... Fun as hell and within my budget but I know I'd get hurt on one (I get hurt on a mountain bike). And the Cannondale Habit... Very tempting future purchase...