I've seen a few done like that (ie full spray down to the floor) and it was more a paint saving exercise than anything (same as factory I guess).  I needed to save a bit for a mate.  I probably went overboard spraying the sides to the level I did - even though they are covered by decals.  Each time I do one I improve on my process - and learn things to do better the next time.  Would I spray to the floor on next job- not sure.  Once I've rebuilt my pins I hope not to have the bonnet up too much. 
The decals are done and dusted, just waiting on some extra long leg bolts then I'll post some pics.

My process is as follows (or will be for next one):

1. Strip cabinet fully and remove old decals.  I prefer the heat gun method, belt sander if all else fails.  Ensure to bring it back to wood to remove glue.
2. Sand with 120grit (float sander), followed by 220grit (float sander).
3. Fill (builders bog) on dings.  Key out any delaminated areas and repair same.  Sand 220grit (float sander).  The corners are the bits which need to be 100% to get a nice finish.
4. Fine fill repaired areas if needed.  Sand 220grit on orbital.
5. Inspect under flood light along length of cab to look for missed areas requiring fill.
6. Prime with autobody acrylic (if using acrylic paints) primer / filler.  Helps to fill grain.  I used K&H (cheap brand, but worked fine).
7. Leave to cure fully for a few days - weather dependant.  Acrylic tends to shrink.
8. Sand with 400grit on orbital.
9. Remove dust.  Prepsol.  Tack Rag.
10.  Paint cab.  I used Dulux acrylic which was paint matched to original. 
11. Once paint cured (couple of days min) I inspected finish.  Red scotchbright pad on areas where decal being applied to knockoff any high spots and to take any shine away to ensure good decal adhesion.  Remove dust, tack rag then install decals.

All up I would estimate at least 25 hours into the cabinet decal / paint job.  Crazy amount of work but the end product turned out OK so no complaints from me.