i've seen a few near fails at the ramp with 2wd trucks, its a steep ramp that gets slick but we always got them out by just standing on the rear bumper.
1) if you have a long tongue on your trailer it helps keep the rear tires out of the water or the algae that forms right near the tide line.
2) put some weight in the truck bed. a couple of sand bags from home depot weigh quite a bit for the $3 they cost, or salt bags do the trick. if you do feel yourself slipping, having somebody stand on the bumper.
my durango has plenty of power but I still worry about the rwd, so in my trucks rear storage I do carry a tow chain and a tow strap, but they've never come out of the the bin, so far so good.