I chose to replace the front vent with a 10 speed MaxxAir with the manual lift. It seemed to be the best all around solution.
The MaxxAir instructions (
MaxxFan Deluxe Manual Opening | Latest ) are excellent and the installation took less than 30 minutes. The most difficult steps are removing the roof caulk and cutting the flange. Hi-Lo was thoughtful enough to have the wiring already in place at the front roof vent opening ... thank you Hi-Lo! Otherwise I would have had to tie the fan wiring into the existing fluorescent ceiling light.
The fan, caulk and sealant were available at the best price I could find at CampWorld ... It is not cheep (about $250.00) but being we seldom hook to shore power the fan will be wonderful on hot nights when the AC can't run.