I had a set of the Toyo AT3s on my green Tacoma...not low noise at all, and they were P-metrics. Great everywhere else, however.
K02s are GREAT looking tire and wear like iron, but I've found them to be lacking in the wet traction area.
My top contenders are the Yokohama Geolandar G015...
Do you have an OBD2 scanner setup, so you can see the actual temp?
For $30-35 you can get the Torque Pro app and an ELM reader for the OBD2 port. It'll give you instant temp of the engine and trans as they see it through the sensors. Lots of other really cool things you can read with these as...
Looks like a cool trip!
Were you working it hard when it was 210*? I've had mine run between 205-210* running down the interstate into a headwind with an enclosed trailer at 72mph.
Make sure all the fins are clean in your respective coolers to let the airflow through.
Drive the hell out of it...don't save it for the next guy.
350s are "cheap" to rebuild and you can get ALL of the maintenance parts.
My DD Tundra has over 235k on it.