The quickest way for you to get a good feel of what its worth would be to search high and low on craigslist, ebay (completed auctions), RVTrader.com, etc. and try to find a "comparable" trailer and see what someone is willing to pay for it.
Did you buy it with a clean title, or is it considered "salvage?" A salvage title will almost permanently detract from its worth as well.
I can give you a couple of comps: A couple of years ago, I looked at a 2002 19' trailer. Interior was mostly pristine, as it had hardly seen any use. The exterior looked like it had been dragged against a telephone pole along the street side. It had a salvage title, and the seller was asking $5500 for it. I walked away from it, but if I had it to do over again, I would snap it up. The guy's ad kept getting flagged off Craigslist because the price was so low people thought it was a scam (it didn't seem that low once I saw all the body damage, though). It eventually got snapped up, though.
There was also recently a 19' trailer on ebay that was up for bid with no reserve. I think it was around a 2006 or 2007. Its shortcomings were that the owners had made some interior mods that many people might not appreciate, and there had been some relatively minor damage to the exterior that instead of doing panel replacements, they had riveted on patches. The auction ended with a price in the vicinity of $8k less than similar trailers without the mods and patches.
So the question is, "why do you want to know what its worth?" It doesn't sound like you are keen to sell. If you are wondering if you got taken when you bought it, sometimes ignorance is bliss. If you are wondering if it is worth repairing, well that's something else. There are plenty of threads on here about fixing hail damage--make sure you do some investigation before putting a torch to your trailer (its not good for the clear coat or the temper of the aluminum). If you are looking to improve the value of it avoid the bondo and latex paint as well!