If you're on facebook, search for "blowing birdies disc golf club" and join their facebook group and post there. Those guys have lots of members with days off during the week so they are constantly playing just about any random Orlando course any given day.. Always a few of their members out at Barnett during the week too. They are very welcoming and friendly. Chances are you will bump into one of them at Barnett if playing solo.
Also note that Bill Frederick Park @ Turkey Lake (10 mins from Barnett) and River City Nature Park (30 mins north up I4) are both better parks/courses to play in than Barnett but Barnett is still a good choice. I just wouldn't go out of the way to play it before Turkey Lake or RCNP if you're looking for best available courses in the area.
