evy,
Good panel and you have the system basics correct. If you remove your kayak at the camping site so that the panel can get full duration of sun, you should be good for two batteries.
The choices involved in upgrading or controller choice are pretty much as BFL13 outlines. A lot hinges on your use now and future use of the 12V system. I'd suggest to start with a single because Canadian Solar isn't going away any time soon (allows for matching panel in the future). If you do start to use a lot of 12V for inverting or other common 12V uses, more batteries, more panel, and a controller that will handle that would be in your future.
Bonne chance!