Mexican Mountain to Spring Canyon is a 9 mile out and back trail located near Green River, UT. The trail is good for all skill levels and primarily used for hiking.
The drive out is fairly gnarly and feels like a washed up river bed especially for the last 5 miles. My friend made it in his 90 something mustang which to our surprise only got stuck once, with the help of filling gaps with rocks when clearance was an issue. But my jeep made it through without a hitch so any 4x4 with a foot+ of clearance shouldn't have any trouble.
The endpoint is a small rock field with a few distinguishable camp sites that sit adjacent to an automobile barrier which also serves as the hiking entrance into the valley beyond, including easiest access to the river.