I suspect Wayne is pretty much correct, just because it is "permanently" moored in that spot does not mean it has any insurable value to an insurance Company.
RVs generally of that age are not worth more than the scrap value of the metal that is there so convincing an insurance Company to underwrite an insurance policy for a few thousand is going to be difficult and not to mention prohibitively expensive.
To put this into perspective, my TT which is a 1984 model I purchased for $700 12 yrs ago. I put just under $4K into rebuilding it from water damage, it is still only worth $700 and it would be a hard sell at that price even though the water damaged wood and paneling has been removed and replaced.
Unless the trailer park specifically requires you to have insurance liability coverage you might be able to get a "renters" policy to cover the CONTENTS ONLY.. But there may be occupancy requirements so ask questions..
Hate to say it, but if you paid more than a couple of thousand you may have paid too much even if it is pristine condition.
