For reference, I used Schedule 40 to the valve boxes, then poly to the heads. 1" for rotors, 3/4" for sprays and the soakers in the gardens.

Latex or oil base.Just spray it on as a mist instead of a thick coat and it will not peal.Think of how many times you've seen overspray on the lower edge of a roof from some wannabe painter.

We bought deck wash at Lowe's which washed off with a garden hose and a spray nozzle so no possible damage using a pressure washer.

One coat sprayed or rolled on works in most cases.I use Home Depot for rentals and  buy tools from HD or Lowe's depending on what I need and what's on special.Dumpsters?

They come once a quarter no matter what to do some maintenance (spray exterior etc) but you can call if anything else is needed. 

I was working on a flip last summer, we sprayed the house in a couple of hours, the next door neighbor was using a brush, took him a couple of months.

I hate masking and my husband's eyesight isn't good enough to spray, so he masks and I spray. 

Should I just spray some ant repellent up there and seal it with caulk?

Consider you will have to replace bedding every time someone leaves (which will be frequent), provide initial linens, constantly spray/bait for pests (especially bed bugs), and will have to abide by an even stricter set of occupancy rules.

@Robert Campbell caulk grooves, thinset wall, spray texture, then paint