RV batteries, generators and solar panels?

I have a question that is probably so basic that is why nobody has covered it. Everytime I mention generators being loud and not campground friendly they boast that the new models are quieter...quieter maybe but noise is noise non-the less and it's not a road I'm willing to go down...ever!

That leaves solar and battery banks right? I currently have 2 batteries and starting comparing prices on solar and it's still quite expensive. Up here in the north a decent solar setup will still run you in excess of $800 CDN. A sealed battery for my RV is just about $100 so I'm wondering how much bang for my buck I'll be getting by adding new batteries? How many batteries are overkill...is there such a thing as too many? I understand the virtues of solar but what I don't have is information about battery banks?