RV Repair: Frame, aluminum frames, rv manufacturers

Question
My family and I are searching for a used RV.
We had an older 74 model, and while I don't think we're "rough" on 'em, we do use them pretty heavily approx. 8 months a year camping hunting etc.
At any rate here's my question.
While our old one still looked nice inside and out, the wood cage that held the sidewalls and roof together started rotting and coming loose until the upkeep just got to be more trouble than it was worth.
I've been searching on the internet to try and figure out, with no luck, what year the major RV manufacturers started building the "cage" with welded aluminum instead of wood.
I've been told that short of a crash, the newer ones are virtually indestructible, but no one can tell me what year to start looking at!
Can you tell me?
Thanks
Buck

Answer
Buck,
   It is really hard to give a definite answer to this.  While some manufacturers have been using aluminum frames since the 80's, others didn't try it until the mid 90's, and some others still use stick framing.  You will just have to check each RV on an individual basis.  Sorry I couldn't be more help.

Darren