Airdog or Fass or ect... are just aftermarket fuel pumps, most also have big hiway truck style fuel filters attached. The stock pump is adequate for stock power, but the added filtration is nice. It is a toss up depending on what kind of power you want to make. There are cheaper ways to get the same thing, but it takes some time and effort, lots of used ones that come up for sale when guys jump to bigger pumps.
Amsoil dual bypass allows you to run longer between oil changes, as there is more filtering media to deal with crap. I personally have never run one so can't say much about them either way.
A full turbo back exhaust is worth a couple ponies and a bit in fuel mileage, but I don't know if the cash out lay is worth the outcome to you. Lots of guys just straight pipe the Cat and call it good enough.
If it is an auto, at minimum I would get a good converter and a shift kit. It will make all the difference in the world. Stock Dodge transmissions barley hold stock power.
Programmers and sticks are where the power lies, but you need to know what you want out of the truck before we go down that road. Most programmers like a smarty, will give you an increase in fuel mileage as they give you a bump in timing, also has top speed limiter increase, and tire size adjustment ect... and of course power.
If this is just a pre trip get ready thing, I would just change the oil, change the fuel filter, buy a spare fuel filter in case you get crap fuel along the way, and head out. A fuel pressure gauge is a nice thing to have, as these injection pumps need a nice supply of fuel or they will burn out.
I think that covers it?