As far as tips on toolbox restoration...if I'm going to sand one down and repaint it, I try to
1) get a box that is worth putting my time and money into...something that is well made and will look nice when I'm done. Most of the effort is in your labor, but you still can spend $30-50 easy on paint/primer/sandpaper/drawer liners, etc.
2) something that isn't beat to hell and dented up...where the drawers close well and just needs a fresh coat of paint for the most part.
I did my first ones in '96...3 drawer Waterloo rollaway from the '70s that used to be in a hospital and a 2 drawer Craftsman top chest from the '60s. They came out so well, that occasionally I'll buy another toolbox and redo it. I like to pick up different styles. I've done seven in all. I sandblasted the first two...but since then I've just hand sanded or used a ryobi sander. You still have to hand sand corners and stuff like that. One of them, a small two drawer box, I took to a paint stripper and had them completely strip it. That was cool...but gets very cost prohibitive with a box of any size.
Some of them I've repainted everywere...inside, outside, and underside of drawers...others, just the drawer faces and the inside. Depends on how bad it needs it.
When I'm done, I buy black rubber carpet runner...from either home depot or lowes...usually HD...and custom cut my drawer liners from this. Also do some measurements and plan before I start cutting so I can get the maximum number of drawers done with what they give. If you're doing a standard craftsman rollaway toolbox, this stuff is perfect because it comes in rolls 6' X 27". I was able to do my complete snap on 7 drawer rollaway in two rolls of this stuff. It sells for $10.97/roll. These liners are better than anything you can buy...at least what I've seen...and relatively cheap.
I've only used spray paint...nothing too elaborate...but would like to try my hand doing a more professional job with a paint gun. Even just using the spray paints though, I've been very pleased by how well they've turned out. Fortunately the snap on boxes I've bought recently are in good enough shape that they won't require any major work...just some touch up in a few spots.
Which leads me to a question...Snap on sells touch up paint for their boxes, correct?
About how much would it be...and do they sell it in regular spray paint size...12 oz? I've looked all over, and can't find anything close enough to the snap on color in conventional hardware stores. I'm sure that was planned!