2007 Tundra Double Cab, 6.5foot bed, 4WD, 5.7 liter

I drove a 4Runner for 25 years, but needed something to haul my travel trailer. Found this truck with 130,000 miles on it and bought it. It runs great. It will pass anything on the road , but a gas station. I put in a K&N air filter, cleaned the mass air flow sensor. I swapped the custom wheels and off road tires for some alloy wheels, Put four new Michelin Defender LTX-MS tires, and put Snake Oil in the oil.

I've managed to get 19 MPG once and 17 regularly on the highway. City is about 13 MPG. Towing is from 10 to 12.
Is that about average?
Is it possible to get better gas mileage than that? If so what do you do, and how complicated is it?

 

Welcome from LA (Lower Alabama)! Good luck getting much better MPG than that. You might do a little better in the city, but there are a lot of definitions of "city" driving. Stop lights and stop signs kill MPGs.