Both Tripod and mast pipe can be found at Radio Shack, Home Depot, Lowes, I'm sure Mennards though I've never looked, I suspect Best buy and, of course other stores.
Camping World and several RV dealers have special things for RV's that consist of a heavy duty base and a "Gimbal" type mount (or ball and socket) so you can set it down then release a latch, "Plumb" the mast and lock it down (Very handy but .. $$$) They shoudl have tripods too.
If you want to go first rate you can get a surveyor's tripod and some places still have mast adapters for those, These can be tied down with a "Claw" or a dog tie so they do not blow over and have adjustable legs so you can level them properly.
Lots of options.
The installer who did my RV was just a generic installer, Had no problems at all. There is NOTHING special about an RV install save the tripod.
It appears the gimbal mount one I described above is no longer in the CW catalog.