New here, but I will add in.
I started camping in my 2012 and also towing, can't do anything with out hitting the bump stops. It is killer on the back.
I have a guage to weight the TW on the trailer and my dealer wanted me to tow the trailer there, had little in the truck other then hunting cloths and the Undercover on the back of the truck. The TW was at 275# or so and it would hit the bump stops at every big bridge, in and out of parking lots and so on.
I call Toyota, the dealer, all told me there is nothing they have to offer and they will do nothing.
Funny thing, if I remember the update with the TSB was Springs and shocks, mine has the 4 leaf springs but for 2012, they took the upgraded shocks away.
The other day I found a local TW member that added 5100 and got his TRD shocks.
I added them last night and today it drives so much better, going over speed bumps, so much better. Yesterday it would hit hard, today it does not. Now this was with the bed loaded, no trailer.
Trailer to come later this week.
Also have Firestone air bags to add to level.
My thought, and truck with no loaded cargo and a TW of 300, should not have a problem, after all I did get the tow package and it is rated at 630.