To do it correctly, you have to know what the current adjustment of your frontend is (or have some reference of what is needed) before you go buy bushings for it, otherwise there's a high probability you won't be able to dial in your camber while maintaining correct caster (and vice-versa).
The only exception to this is if you use the fully-adjustable two-piece bushings (Ingalls 59400, Moog K8986, Spicer/Raybestos #6122025, etc.). These you can dial to any degree amount needed without having to replace the whole bushing (and are handy to have should you need to make adjustments in the future).
As for the spacers, if your truck is a Supercab, chances are good you can use them without a problem.