Westwoods in Guilford, CT has miles of trails that you can connect to form enormous loops. My favorite loops involve trying to hit every trailhead, or at least the trails that lead to those trailhead.
Moose Hill Loop
I start at the Moose Hill entrance I follow the pink trail out and wind on several other trails (violet, yellow, white) to Lost Lake, then on to 146. I return on orange, white, green and blue to the Peddlers Lane entrance. Next blue to orange to the board walk entrance. Then double back to green, up to lavender and back to the Moose Hill entrance.
This loop is big and recommended for pedallers with a few hours to spend riding. In most trail systems, I’d recommend an XC bike, which is fine and fast, but repeated loops of this type in Westwoods, will lead to your bike falling apart. That’s because there are rocks and roots and muck aplenty. You will get your pivots wet then grind in mud. You will push your suspension beyond its spec and if you have fatigued metal, your bike will snap, eventually. A few riders are clever enough to ride XC bikes nimbly enough to avoid this, but for the rest of us, use an All Mountain or light Freeride bike in Westwoods. It will last longer , let you down less, and cost less in the long run.