I have 2 60 watt panels flat mounted on my roof, run through a e-bay PWM controller. They keep battery full when at home in driveway, and on road in sunny spots.
I have a 100 watt portable panel that can be set up to about 150 feet from RV. I have 30 feet of #10 with MC4 connectors on each end. I have 2 12-3 extension cords that can extend up to 130 feet; they have standard 3 prong plugs. I made up 2 adapters, one female, one male for the three way plugs to MC4 connectors; used neutral and green for negative side, hot for positive. I tie this panel directly to the battery.
You need to be careful using this setup, but even a day in bright sun would not damage a fully charged battery; just give it an equalizing charge. You must feel comfortable with some knowledge of batteries to use this, but its not rocket science. It goes without saying you need to make sure you don't plug the extension cords into 115 and the battery, I don't know what it will do, but I'm certain it aint good.
We have all lights changed to LED, and are pretty careful with usage of TV, DVD player, Radio, etc. Furnace will eat the watts, only time we have ever needed the gen since adding panels.
Regards,
Doug