5,000 lbs will be 6,500 lbs loaded up...I would not be as concerned with the overall length. I mean, it's a concern for sure but keep it around 30ft and you should be good to go. The front profile of the trailer is something I concern myself with. A slightly heavier, low CG TT at about 9.5-10.5 ft tall with an aerodynamic front profile will pull easier than a 11.5-12.5 ft TT with a nearly flat front profile...the reason is aerodynamics. A shorter profile with a more aerodynamic front end takes less effort to pull through the air.
Just something else to think about. Either of those trailers are well in a well equipped (tow package) Half Ton SUV's capability.
Thanks!
Jeremiah
