it will cost a bit, but go with the bigest alt you can get for the truck. then add a second battery, you will need a battery isolator. this way you can run the second battery for a inverter and to run more 12v stuff and not run down the cranking battery. depending on the size of inverter you get you can run any thing you want. if you do wnat to run power hungry tools the truck will need to be running or the battery could go flat in no time.
http://www.neon-john.net/RV/Electric...ion_relays.htm