First...thanks to all for amount of info on this site. Havent posted many questions as there is almost always the answers I am looking for somewhere in a previous post.
Working on a 86 chevy truck, mostly a practice project before someday attempting a nicer one.
So far I have done all the body work on the cab and primed in epoxy. My plan was to only prime with highbuild on the outside as there is very little interior that will be seen once trim ect is installed. I had planned to do the same with fenders/hood/doors. Would just prime the entire panels with epoxy then the outside with highbuild. Would then block everything and eventually final paint on the inside of all panels and cab (after sanding the epoxy) before reinstalling them. Eventually (next year) would hopefully be ready to paint exterior all at once.
Does this sound like an acceptable way of going at things? Any issues you see with my plans? One of my main questions is whether it would affect the highbuild primer sitting for a year? I would do a clean and final wet sand prior to doing the final paint but was wondering if they should be sealed up for the time being?
Any help would be appreciated, thanks again

Build primers tend to soak up contaminants when left for long periods of time.
If you get it all guide coated and blocked out then shoot a coat or two of epoxy over it as a sealer. When you get ready to paint you can clean the car real good and then wet sand with 600 grit. That will give you a chance to see if you have any new issues. You can apply filler or spray more build primer over the sanded epoxy if necessary.

Thanks for the reply, that was my concern. My goal is to work at this in pieces thru the summer and then reassemble and do some frame/drivetrain work thru the winter when painting wouldn't be ideal with my setup. Hopefully have everything ready for final paint in the spring.
Planning on BC/CC. Should I be going to 600 before the final epoxy as we'll or will a courser grit be enough (since I will use 600 before final paint as you suggested)?
Thanks

Coarser grit is fine since you will be doing more sanding when it comes time to paint.