The masts and rings that we used at field day came from Max-Gain Systems. You can find their website here. Don’t know how well their rings would work with standard PVC. Maybe some combination of flanges that you could glue to the PVC along with a hose clamp for support and then drill for guy connections would work? A good place to get this stuff would either be Home Depot or County Store in Milford, NH. As far as a base goes, your can make one using some pressure treated lumber. Here’s an article showing what we did for our mast at our home QTH.
Hope this helps,