The Green River and the Flaming Gorge reservoir, and the Flaming Gorge canyon can make some interesting places for adventures for Dungeons and Dragons (whatever version you prefer).
Rafting on the Green River by ~Atlantean6 on deviantART
River rafting on the Green River through the canyon can set off an adventure of dangerous proportions! There's a lot of places on both sides where the enemy can snipe at you! The adventure can start as a river run to run supplies to another town, and the dangerous canyon is held by orcs, bandits, or whatever. Your choice.
The player characters are hired to protect the shipment. Can they survive their enemies? Run the adventure and see what happens . . . :)
Naval Battle Royale by ~Atlantean6 on deviantART
Or add a second dimension: the group is competing with a NPC group to run supplies down the river. The competition could get fierce if their competitors attack your group with sword and spell . . .
A Copse of Trees by ~Atlantean6 on deviantART
Not an adventure in of itself, but a location or Adventure Site. Here is a copse of trees, where you can put a mountain dwelling culture. Mountain dwarves, gnomes, halflings, orcs? Whatever your imagination can think up it can go here!