It sounds like you are going to rack up a lot of hard miles on your truck so the verdict goes to a diesel type ending which among other things you will pay a little more for gas but in the end get better gas mileage. You can get a little more detail at this site to really get a good synopsis of the benefits of the two check here http://www.trucktrend.com/features/tech/163_0210_diesel_vs_gas/index.html. As for Ford or Chevy, well that is an age old battle that may never have the correct answer, however I do like the increased fuel economy of their gas trucks and the perceived "green" that is ecologically conscious way they have been re-branding themselves lately. So, In the end my recommendation would be a Ford diesel type truck. I hope this helps and good luck.