Yeah, I can see it being a problem trying to have something to be able to attach nest boxes to. And to be able to support not only the weight of the nest box, but of multiple chickens since they will sometimes stuff themselves into the same box at the same time would be difficult using PVC unless you were using at least 2 inch pipe that wasn't prone to bending. Being an a-frame with a wide base will help it stay put when other things won't though.
My PCV chicken tractor I posted before didn't mind the wind. It's light enough to pull around by dragging. It didn't budge in winds because I think it's low enough that the wind can't get under it. I have the closed off end to the north and your looking at the west end. Unless it's a hurricane, wind isn't blowing from the southeast often which would lift it. Although I do remember a few years ago a sudden burst of wind from the south took a few calf hutches for a tumble including the 500 pound 'group hutch'.
This tractor worked great, but like I mentioned it was tough fastening nests. I don't have any roosts although I have a brace in the middle about a foot high that they didn't use. I have the pieces to make another one including the 45 degree wye and a 4-way Tee which is used at the top to connect the legs at the middle. A 3-day 90' elbow is needed for the top at the end legs. I think it cost around $200 per tractor which isn't cheap. The pieces mentioned can't be found at many hardware stores in 1 inch, I had to order them online.
Here in TX PVC is really too light for the winds unless there is a close windbreak or you can get it tied down well - but even that is no guarantee. We have PVC hoops over our garden beds and we often have the wind pull up stakes and pull screw eyes out of wood that we attach our tie-down ropes to. We're always having to put the garden hoops back together after a windy day. I still haven't figured out how all these people put up these really big PVC hoop houses to garden in and they don't have a problem with the wind tearing them apart. I know some people that have tried metal electrical conduit thinking it would add the needed weight to their coops but even that didn't work and they lost their birds in a thunderstorm. We don't even have to have a storm to get gusts of 40-50mph and we get swirling winds from all directions.