Here is a few pics of my current trailer and suggestions. I have had both aluminum and non aluminum trailers.
My current trailer is aluminum. (less weight to pull but more expensive to purchase)
Tandem axle (better ride, less abuse on inventory in the trailer).
Torsion axles are a little more expensive then spring axles( but less bounce and abuse on inventory).
barn doors vs ramp. Yes you can get closer with barn doors but a ramp door is much easier especially if your by yourself!!!
Last advice shop around and don't buy the cheapest out there (lesson learned long ago) inspect it well, make sure if you buy a 12 foot or larger with tandem axles you install a brake controller (DOT Law) . Install your own Etrac its much cheaper to buy somewhere else (harbor freight sells it)
Good luck, I looked two months before I bought this one.