Since you have a basic RV set up you might as well use the Rv Chemicals. They don't last long but are effective for the time your on the boat. This would practaclly require a pumpout after weekend activites but you wouldn't have an odor problem.
I disagree, Rodd. As hot as it is this summer, nothing will work for more than a few hours without enough ventilation to the tank to keep it at least somewhat aerobic...and chemical products have the shortest effective lifespan. Besides, that his holding tank is an aluminum pontoon creates enough of an issue without adding chemical tank products to the mix. The more "benign" he can keep the contents, the longer the tank is likely to last.
Sunrise Cove is a nice marina...and also close enough to Browns Bridge to make it easy to get under it and away from the craziness south of the bridge. One of my favorite ways to spend a day was a lazy trip up the Chestatee and watch literally dozens of huge turtles sunning themselves on rocks and logs....fall was a great time to go too.