This is what my normal tune up package consists of (and my truck had the exact same amount of miles on yours when I bought it):
1. Plugs - OEM AC Delco Iridium plugs. Do em once, never do em again. The Iridium delcos last for 100K miles.
2. Plug wires - again, OEM Delco or Bosch wires are what you want. Not necessarily needed, but there is a good chance that you'll tear one of the old ones trying to get to the plugs, so its nice to just throw new ones on while you've got everything apart.
3. Air filter - or in your case, an aftermarket intake. PM Max for a good deal on an AEM Brute Force. Excellent, excellent intake. I'm running one and I love it.
4. Transmission pan drop and fluid change. DO NOT flush the transmission. Pan drop and fluid exchange only. Replace the trans filter while you're in there, thats very important.
5. Oil change with the 5W30 of your choice and a Wix or Delco filter.
6. Seamfoam through the vacuum line into the engine. This will free up alot of carbon and gunk. Great stuff, just follow the directions on the can.
After all of that, she should be running great.