Hi and a second welcome. Lots of good coaches available, so you don't need to worry about letting one get away, as others will be available.
National Tropical are well thought of coaches, a solid C+ to B mid level coach. If I remember from when I was looking, these National used the CAT and Freightliner chassis in this era?
When buying remote, if it is from a private owner, ask them to copy and send/fax/mail you the maintenance history for the coach. If you get a good feel from these, then take the next step and pay for a private PDI. This will confirm or back up what the seller is staying, and the documentation has shown. Also have the person doing the PDI for you pull oil and trans fluids to send in for analysis.
This will give you a very solid baseline, and you will know what you are buying. If the tires, chassis and coach batteries, belts, hoses, air brake catridge, Lube Oil and Filters, Air Cleaner, Generator too in this mix - all need attention, you are looking at between $6-8K on top of the purchase to get the 'known to you' baseline complete. If the 'documented history (receipts, receipts, receipts)' is backed by the inspection, then - then you may be able to get in and go
Best of luck on your search, but before taking the time to go look, I would arange a independent inspection as the next big step.