High Lakes Tr6200 is a very easy OAB ride, which could start from Fish Lake or from Lake of the Woods.
Note: High Lakes Tr6200 is a gravel trail.
The Brown Mtn to High Lakes Loop may be a better option.
Also check out Rye Spur Tr3771.
The gravel-packed terrain is fast enough that merely riding the 6.3mi High Lakes Tr6200 section OAB may not be enough for most people, so Mountain Lakes Tr3721 and Fish Lake Tr1013 extend the OAB ride, with a 1000' climb (6% incline) on the Mountain Lakes Tr3721 ascent.
Fish Lake Trail 1013, High Lakes Trail 6200, Mountain Lakes Trail 3721
Aspen Point Campground, Doe Point Campground, Fish Lake Campground, North Fork Campground
Ranking consistently applied to all of the listed trails.