My advice would be to be sure and get 16" wheels and tires, at least 24 foot and a winch.
Overkill for what he needs. I did look at a set of 16" 6-bolt aluminum wheels and tires for $1000 yesterday, just can't justify the cost. As much as he is going to use it the upgrade wouldn't be cost effective, he doesn't need 5200 lb axles either...
As someone who has towed a whole lot I respect your opinion, however after he blows out a few 15" tires he might feel different, if buying new I don't think (but don't know) if it would be that much more.
I recommended 24ft for resale value and the winch for convenience.
I agree with all your statements, if he was planning on towing a lot. I did blow out 4 tires last year while towing 120K miles, but most of that was on me for knowing the tires needed replaced. The one thing I do recommend is to inflate your tires cold 10 lbs more than the tire rating says, and keep them covered when the trailer is sitting...
If you but a trailer for resale then you are doing it wrong, though most enclosed trailers lose little value over the years. 24' is always the best bet...
