My trailer was a home built 16' dual axled horse trailer axles (torsion bar) 7000lbs, 4 wheel brakes,all 2x6 channel frame with 2x6 channel tongue 2 5/16" ball.
The builder of my trailer was also a sales rep. for a company that suppied most of the trailer manifactures in the pacific northwest. His design was a copy of what he thought was the best from what he saw during sales calls.
I had mine for well over 10 years and I have to say it's one of the most used items I've ever owned, so don't go cheap.
In Washington state any trailier over 3000lbs have to have brakes on all axles, now in Texas were its flat maybe single brake axles are maybe ok but when it comes to me you can never have enough,and the reason I say this is because you alway end up over loading them because thats what we do. In the rockies or cascades (Wa. & Ore) you can have 20-25 mile long down ward grades were there are truck sand traps every 5 miles if your brakes fail you'll be shiting razor blades. Most flatlander have no idea whats it like to travel the western states.
After 10 years the #1 thing I've come to like the best are the torsion bar axles, you get true 4 wheel independent suspension. My reason for saying this is I've found so many times you're are going to get something empty or you're coming back empty and its like its not even there, and when loaded it's even better. Another thing about torsion axles is lower ride height.
When it comes to size yes sometime I wish I had a longer trailer but even a 16' trailer it seams you need a 1/2 a football field to turn around so think about that before buying bigger plus home storage when not in use it takes a lot of sq. footage.
About 5 years ago when the wood deck died I made upgades,I found a ocean going refer. container with a alum. deck which saved about 150+ lbs plus I added more tie down D rings because they just weren't in the right place for all the things I seamed to carry. And at this time I extended the tongue about 20" and the reason I did this was the tongue jack was part of the hitch and you could not put down the tailgate and if I had my 10' camper I would have to add a 18" stinger which changed the hitch point and lenthened the distance from center line of axle (not good).The 20" also made the backing up and jackknifing into parking spaces easier plus again even better towing.I also added a folding trailer jack because the old one was bent from scraping the ground.
When I bought it the trailier it was already built and the 7K axles were part of the deal, 8K axles (6 lug wheels)again because you are always pushing to its limits. This is the way I'd go if I had had a choice. If I went 18' I'd do a drop tail.
I would never load a vehicle on backwards!!! Use a lesser drop hitch or air bags to adjust ride height. And don't buy a alum. adjustable drop hitch I known of 4 different people were those have broken to a tune of about $100,000 of losses most are china crap, steel ones made in the US are good.
