These 14ft box uhaul are rated for hauling upward to 10k lbs, which is well within the parameter. If anyone think this is not a good idea, please let me know.
First and foremost, you must remember that I'm not an expert, but the people with the knowledge will be along shortly.
After a few "google" searches I was able to determine that the TT you are considering has a GVW of 10,680 Lbs. and, if Uhaul truck is rated for 10,000 Lbs., then you are in unsafe territory from the get go....
I realize that 10,000 Lbs. mentioned was a guess on your part, and I'm pointing out that you can not be guessing.
You must get particulars of Uhaul truck to be used as TV.
To me, this type Trailer is not a "Travel" Trailer, but something to be moved infrequent. With that said, I would still buy a WDU (Equal-i-zer or Reese) to use when I moved this Trailer. And especially towing that distance with a 14Ft Box Uhaul vehicle. (you can not see what is happing back there) Look into another type truck for towing, maybe a "flat bed".
I realize that your excited about purchase and just "jumped the gun" with Post.... hopefully others will get on forum and relate their experiences and advice.
GOOD LUCK, and have fun with the purchase process, be safe.