Any thoughts on upgrading your trolling motor batteries? We had similar situations when a group of us would do a cast and blast up near Long Lake years' back. We'd be there fishing and duck hunting for a few days and never had an issue. Didn't bring a generator, but did use a 15W solar charger at the end of the day to top off the trolling batteries. My setup for the trolling motor/batteries were two Deka Intimidator AGM group 37's run in parallel to power a 12V Minn Kota 55# trolling motor. Windy as heck up at Long in the fall, so I was on the trolling motor all day. Got done fishing in the afternoon and hooked up the solar charger. Worked great.
If you're fishing for longer periods of time, I would suggest keeping the solar charger on the troller batteries while fishing. But definitely think about upgrading to an AGM battery (or batteries in parallel) for the trolling motor. They last much longer than a standard wet-cell deep cycle. Granted some AGM's can work for a starter battery too, but you have to ensure the CCA's are large enough to turn over the outboard. Deka AGM's can also be used as a starting battery. I've used them for starting batteries as well as trolling motor batteries in my old tri-hull with a 50HP Johnson and also currently in my Champ 181 with a 150 Evinrude.