Rolls72

Im looking for other people that own a vintage rolls international travel trailer. I recently aquired one and know nothing about it. Hard to find any info online. Mine is a 72 envoy

Forgot to mention There is no outside access panel

I have a 30ft rolls international envoy either a 1972 or 1974 with a suburban furnace.i noticed The fan wasn't kicking on when I turn on the thermostat. Upon further inspection I realized it was locked up with mud dauber nests. My question is how should I go about removing the debris in the furnace? (The fan did break free and I immediately shut it off to prevent any further damage) it was all in working order two years ago when it was last used