I think you have to charge the trolling motor batteries at least. 8 hours on the trolling motor is going to run them down, you don't have a choice. Not sure what to tell you though. Do you have a portable generator? Maybe you could do that. Otherwise maybe you can find some kind soul to allow you to charge off their outlet, maybe have to pay to do so. Make your reservations this year for next year if you can find a place.
"If worms carried pistols, birds wouldn't eat 'em."
- Darrell Royal