Hot Springs eh? Love the area, been there several times - as a matter of fact it's time for me an the wife to get back there and enjoy the area!
As far as your vent fans, I have heard a lot of good things about the fantastic fans and looked at them - but for our 76 Argosy we are going with the MaxxAire deluxe :
as I have heard good things with it also. It appears that I will have to open the opening up a little but doesn't seem to be a big deal (nothing that a pair of tin snips won't solve). So THAT BEING SAID, if anyone is interested in some original vent fans (one is powered) let me know.
Good luck in your travels and keep us posted -