Make some hooks where it can hang from the top of the slide, then use some small C clamps at the bottom to secure it. That should be solid enough to support the extension to the exhaust pipe. I'd design it similar to a GenTuri so that the generator exhaust draws in cool air to keep the pipe cool, plus cooling the air down will allow you to use CPVC, least it should.
Now-2014 Sierra 346RETS 5er BUB
Then-2002 Keystone Springdale 286RLDS TT
Nights camped in 2014-28, 2015-127, 2016-10