Marshall creek if you're careful. Its sandy and would be fun on a kart, but its a little rough in places.
Directions are in the Marshall Creek Forum Below.
Personally I like Rocky Ridge just fine for a day ride. Its not as far north as Gotcha park seems to be. Take 51 north out of Decatur for about 15 miles and when you pass FM 455 watch for it a mile or two on your left. Theyve got a big sign. You won't be able to explore the whole thing on Karts, but there is definatly some good riding out there.
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2006 525exc
TORO #C180