The 5.3 will do the job. You might not have a 3.73 rear gear ratio without a tow package, therefore it might seem a little sluggish ascending hills.
Tranny cooler. Don't cook the tranny.
LT tires to carry the combined load.
7 way harness on the truck , for trailer lights and charging the trailer battery.
Trailer brake controller in the truck to operate the 12v elec. trailer brakes.
To lighten the TT . ( doing the following will help a little, water being the heaviest item)
Run with holding tanks empty.
Carry as little water as you need to flush the toilet. Don't forget the water heater holds 6 gals. Its up to you if you want to drain it .
Downsize propane tanks to one single tank or a pair of 20# tanks.
Use the smallest 12 v battery on the tongue.
