Got all the body parts needed for this spring/summer project. Some questions

[chevymotocross]

Today I spent $400 on a package of all the parts/pieces needed to fix up my 87 silverado shortbed this spring/summer. Today I bought 2 oem fenders in great condition. Also, 2 oem power doors. One of the doors is excellent. The other has been re-worked along the lower skin (it's in primer/bondo). I also received a full new rocker and 2 supersize cab corners. Couple weeks ago, I bought a good used bed.

The door with the bondo along the lower skin. The guy I bought it from was a body man and he said he fixed it correctly. Should I really strip away what he did and "see for myself" or, should I trust it and just have it painted over? I notice a crack already in the body filler. 

My plan was while the bed is off, to grind down the frame and paint it. Or, should I undercoat it? The underneath of the bed, I was going to use a rust converter, like por 15 or ZeroRust, but someone told me not to do so as those hold in moisture. I was told to instead, prep the underneath of the bed, prime it, and paint it with rustoleum. What do you think?

Any tips on installing the new rocker panel and cab corners? The cab corners I received are "supersize". They are pretty darn big. I don't think the cab corners are in need of that much replacement but should I use the full replacements anyways to be safe?

I have pretty much what I need besides supplies. I am going to have Maaco paint the truck. I am going to strip the truck, prep it, and have them spray it the same color (black). My father did this to his 85 c10 years ago. It came out great and lasted quite awhile. I guess if you strip and prep the truck yourself then Maaco is ok?

I will also unfortunately have to find a beater car/truck to drive to work while doing this project 

Any other tips are greatly appreciated. My dad did this to his truck years ago, has experience welding in cab corners, so I think we should be fine. I am a bit nervous when it comes to body filler, but I have been told it isn't so bad.

[78 Chevyrado]

If there's already a crack in the filler, get it all off and start over.  It may be cracked because it's too thick.  If you can, look inside the door and you'll be able to see the damage real easy,  I think it can only be 1/8" or 1/4" thick. 
  I have had good luck with macco on a few DD's i wasnt to worried about in the past.  I would say do not let them do any body work, and prep it for paint as best you can before they ever even see it.  Their prep is lacking, but some of them do spray the paint well.  If you do any of the prep work though kiss your warranty goodbye, but thats true anywhere.  If any of the paint is faded badly, sand it to bare metal.  if they paint over faded paint, within a couple of months the new paint will be faded there too.

I've never used por or any of that stuff (haven't need it)  but I hear nothing but good stuff about them.  I'd probably use por15 if i painted a frame.

One tip i've figured out is get one of those foot-long sanding blocks, not the small square woodworking ones, and dont sand anything by hand if you want it to be flat.

[chevymotocross]

Great information thank you! What are the best ways of removing filler? Simply grind it out or pry it out from the small crack?

[HAULIN IT]

I'll try to help with some of your questions. I agree with removing the filler on the door that is cracked. You need to be sure you have a sound base to start with, however the crack just maybe from a little rough handling while the part has been moved around. Some sort of a sander with 36-40 grit (even 80) will remove it.
 As for the cab corners, Trim them down, only use what you need to replace the bad metal you have. Basically the same for the rockers, as low as possible. I like to cut the front & rear corners "L" shaped (especially the rear) it allows the panel to be pushed down a little easier.
 Unfortunately I disagree with 78 Silverado, painting over faded paint is not a problem. Now if it's checked, cracked, peeling, ect. it needs striped, but faded, sound paint just needs sanded with fine paper & either primed or painted. Have Fun! Lorne

[chevymotocross]

Thanks for that information! Will post pics of the project once I start it (when the weather gets warmer!)

Only thing I am dreading now is trying to find a dependable cheap driver for a month while I work on the truck 

Stinks but I can't drive the truck while doing this work.