Is it legal in Fla to ride in the grass along side the road?
What county do you live in?
Regardless, I don't think riding on the 'right of way' is legal in ANY county in Florida.
In very few counties, you can ride on unpaved roads LEGALLY. But again, there are very few counties that did not opt out of this Florida law.
Your best bet is to check out the Ocala National Forest, Croom State Park, and places like the MotoPlex in Madison, FL. If riders are under (16) in the National and State Parks they must have attend an ATV certification class.
If you don't ride with a helmet, you are asking for trouble. An 11 year old in Jacksonville just lost his life because he wasn't wearing a helmet while riding.