Hole saw, pilot hole, cutting oil, low speed, and drill press if possible. Drilling holes ½ and up is difficult with a hand drill if you can use a drill press or magnetic base drill unit. If you want a cheep alternative to a magnetic base drill for drilling holes on the truck you can adapt a small cheep ($65) bench drill press as a clamp base drill unit. You can see how I drill holes including hole saw 2 ½ holes in the frame which in places is two layers of ¼ so you are drilling through ½ inch.
http://www.canadianmilitarypattern.com/Tools.html