I would check out this blog entry (warning it's long) on people doing what you want to do: boondock on solar. I don't think you are going to get by on one or two batteries nor will a 100 Watt panel be enough:
Handy Bob'sWell reading further down the blog and it's very long, you can get by with a 125 W pannel and a couple batteries if you are very frugal with power use. And if the panel is wired correctly with large enough wire and the controller is placed near the batteries and set at the correct voltage (14.8 V).