Thanks for the flex line advise Johnnyk81. I'll look into it.
For the copper, here is an update. I finished all the soldering runs. My concrete bit decided to give up the ghost so I still have to anchor the piple at the outlet area and that final water trap, but I'm otherwise complete. I will have to solder in (or SharkBite) something at the compressor end but I'm still pondering what my flex line will be...
All in all its a good 35+ feet 3/4" copper. I can't say I want a career as a plumber after this project. I just hope there are no leaks!
here is the second half of the run:
I put in two stair stepped runs with water traps
For the filter I'm reducing to 1/2 and I purchased this SharkBite connector, so I can attach it to the filter and then simply slide the assembly on. Should work..