How the heck does a 5700lb TT have a tongue weight of 800-900lbs? Heck my 7300lb TT had a 900lb TW @12%
12% of 5700lbs is 684lbs.
To the OP check your door sticker for the Tread Act sticker about max cargo. Passengers and the TT tongue weight are included as cargo. Get that number and work yourself back from there. You need to make sure you don't go over the trucks GVW. If everything works out numbers wise then make sure you get a really good WDH like a Reese DC or Equalizer with 4pt sway. Stay away from those friction bar devices that are added. Get an all in one WDH.
As far as power to tow it. Well that's subjective at best. Some don't mind the sound of a small V8 screaming for mercy while climbing grades. Others, it's music to their ears.