My wife's H3 Alpha gets around 14mpg average on 35"s and 9 to 10mpg towing, so to be only 1mpg off from that with the Tundra on 35"s and being able to tow 4000 more pounds than the Alpha, it's a pretty good situation for me. Plus, the Alpha runs on premium and the Tundra runs on 87 octane, a savings of .43 per gallon. Most of the F250's and 2500's I looked at were averaging around 10mpg towing on diesel, so we did the math and it was significantly more efficient for me to get a 87 octane tow rig.
Outside of towing, this truck may see 4000 miles of driving per year, but in reality I bet its closer to 3000 miles per year. My daily driver is my race rig and I bet I didn't put 3000 miles on the jeep last year.