There's approximately 10 miles if you follow all the trails available. Conditions vary depending on which portion of the trail you're on. What you're actually riding on is the fill left from when they originally dug the lakes in the park, so conditions go from rocky in some areas to hard packed sand in the forested areas. For the majority though I'd say the trails are nicely packed sand. About the only warning I can give is that unless you enjoy swimming your bike through gigantic puddles, avoid the park after a good rainstorm. The lakes have a tendancy of overflowing into the trails when it storms.
"Take I-595 get off on the 136th Avenue exit, this puts you on Westbound State Road 84. Continue W on SR-84 past 136th Avenue to the next light, Weston Road, and make a right there into Markham Park.
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