Solar Panel ... This a good one to start with for my needs?

I agree, stay away from the kits. They may be easier but the convenience is costly. I would suggest checking the craigslist in your area. Here for $100 you can pick up a 180w panel and my 230w portable system cost me $200 for the panel, MPPT controller, extension cables and all.

I would drop the batteries a bit too before hacking up your trailer. I'd cut the legs and if nothing else drill and bolt in the extensions.