If you want to boon dock I'd bump up to at least 400 watts and if you want to nearly eliminate generator use I'd go to 700 or 800 watts.
I can't agree with this statement; I have a 165W panel and it keeps my batteries topped up - so much so that I have not used my generator since using the solar panel. I've boon-docked during winter months in NJ and even on cloudy days, my solar panel has replenished the batteries.
Having said that though, I use a Buddy Heater as a supplemental heater to reduce the amount of time the propane heater is running and I switch off the fridge during the night.
But all in all, 165W has been sufficient for my needs.