Yes, the bike shop gave you good advice. The Clermont area offers some really good cycling roads.

The best way to get to the trail head from where you are is to scoot over to the Floria Turnpike, take it North until you get to exit 272 (Clermont exit). Exit to the right here and, take a left on Colonial Dr which is Hwy 50. Go about a mile and there will be a convenience store on the right and Hwy 438 crosses here. Take a right then an immediate left on Old Hwy 50. Follow for about 1/4 mile and you're there. There are signs but, there is some road work going on and you might miss them. If any questions stop at the convenience store and ask directions.

There is plenty of parking at the trail head along with restrooms and a rental bike shop. Its a nice place. Like kjc said, riding around the lakes in that area is very pretty. There are some hills around too if you want to climb some. You can download some route maps from the Florida Freewheeler website. The Orlando shop can also give you advice on routes.