We knew the furnace was old (over 20 years), but it had not been used for the last 10 years. That could be good or bad.
In our case, it was both. Yes, it works. Yes, it is ancient, inefficient, and we have no AC.
The purpose of having the techs come out was to ensure the furnace was operable and to clean out all of the duct work (we have enough wigs of cat hair to supply the entire mobile home park; we have no desire to provide them to the entire city).
Discussing the immediate future with the tech, Julie found out that if we replace the sub-floor in her office after they clean the ducts then the job will not be guaranteed. So, we get to put off cleaning out the ductwork. During the furnace inspection, the tech had to crawl under the house to check the cross-connecting duct between the two halves. That needs to be replaced.
He also found the following underneath (cat skeleton):
To the tune of $5500+ we can get a new heat pump system, duct cleaning, and new cross-connecting duct. Though I kind of expected this kind of hit, we are looking at getting a quote from a few other places before jumping.