I suppose this could be in the WTB section but I have to be location specific, i.e. northern Front Range Colorado.

I am looking for an on/off road bike to use at my favorite locations in Park County. It will be used to ride on tame dirt roads or fairly rutted roads in the national forest, but it will mostly sit at a friend's house. What can I get under $1500 anywhere between Fort Collins and Denver? 250cc is preferred. Do you know anyone who wants to sell an older but reliable bike? I'll can pick it up from May 1-6. Thanks for any help.

Looks like I'll have to shop Fakebook Marketplace and other online sources and hope to find something in a one-week period.

Can you recommend any dealers from Denver to Fort Collins that you'd trust to sell a decent used bike?

heh, you're about a year and a half too late on the "cheap bike" thing.  And with spring sales in full effect.... good luck finding any inventory.
The entire powersports business has been nuts, both new-vehicles and parts/maintenance.  

Might have better luck on ADVRider, there's a regional flea market thread, as well as the site-wide flea market.  
Only dealer I go to anymore is Steamboat.

I'll be here all next week. Still looking for a bike under $2K. Thanks for any help.

Our shops have some moderate priced used stuff, but it’s grand junction.
Look into Park county’s road restrictions, they have banned ATVs on a lot of forest service roads there.  If you put a plate on the bike though would be no issues.