Georgetown-Rowley State Forest has all types of terrain from wide, gravel trails to tight, tough rocky and rooty singletrack. Definitely bring the bug spray. A main fire road runs from the trail head into Rowley and 133, and there are many trails off of this that again range in technicality, length, amount of obstacles and hills. When its wet, you will get muddy, lots of standing water at times. If you pass over 95 and take the first right and continue to take a right each time there is a fork, you will eventually go past a beaver dam and get onto an esker that will connect you to the Esker Ridge Trail in Rowley. All of this is part of the Bay Circuit Trail. Best bet is to get a copy of Stuart Johnstone's book about the 25 Best Places to Ride Near Boston. G-R is fairly easy to get lost in the first couple of times, but eventually you'll get use to it and find your way out.