That's heavy I had 5 more plugs put in last year it was around 15K parts and labor. We trench and put the plywood/posts up, they do the hookups.
6" .219 wall for air was like $11/foot last I looked so you're looking at about 30k for pipe delivered if KS is like 2500 feet long. You could do 4" air too for prob $8/ft. Need ball valves too. Might be a toss up putting an air line vs more plugs. Only team Magic knows whats best!
They already has their Arecos.
We went full 8" @.375" everywhere when we replaced everything in the base area. Even air! I want the next time they need to be addressed to be my grandkids' problem. The only thing that got 4" was water return lines, which are only providing backpressure and safety flow anyways. More importantly, we took out several hack job pipe "repairs" that literally consisted of 8" pipe with a flat plate welded on the end, a little hole flame cut into the plate, a 6" 90 degree elbow with another similar flat plate welded on the end of that, and back up to 8" again. We knew something like that was there due to mathematical deficiencies observed at hydrants above it, bit I still couldn't believe my eyes when we unearthed it/them. Also our West side feed was a 6" valve in the middle of 8" pipe all this time! Unacceptable!!! Our wide-open sustained pressure increased dramatically after we fixed everything, which really helped us get that water out there as well as run low-e guns higher up, not to mention improves start speed and shutdown safety (neck downs can hold water which will freeze and can create jams when restarting etc.)
It's such an interesting situation to be in because the system was designed as a full loop originally, but prior regimes turned it into a dead head tree and replaced a bunch of 8" with 6" in areas we are still pulling out, especially going up Wiz. Give me a few years though and we will have this baby purring like a kitten again, better than it ever was for pennies on the dollar. It's a daunting task to try to plan this all out in an incremental fashion that is both attainable and affordable, and in a way that's in line with how we're trying to expand our early season operational plans a la Green Chair and a Turkey Day opening date.
My OCD has it's hands full, that's for sure. Every time we complete a project I sleep good for like a week and then it's back to having long conversations with my ceiling and hours spent in the "war room" scratching my head, reevaluating timelines and budgets etc. when reality's inevitable curveballs come screaming in. Magic is such a complicated organism it's tough to stay on top of, but we are doing it pretty damn well IMO.