There are good roads to the west of the forest, if you take 40 towards the city of Ocala. Silver Springs is that way, too. I led a group ride in that area last summer, I can upload the route sheet if you're interested. North of the forest is the Fort Gates Ferry. It's a neat little 2-car ferry boat that crosses the St. Johns River. There's a few miles of dirt road to get to it.
Planning on any dirt riding in the forest? ONF is mostly sugar sand and the V-Strom is too heavy to be much fun in that. It's doable though, if you're stubborn enough. If you stick to the bigger forest roads it's not too bad. They're mostly hard-packed, but you'll still come across patches of deep sand. Again, I can recommend some specific routes if you're interested.
- Jet Jaguar
It's not an adventure unless you need a tent, a passport, and a leather glove for your shooting hand.