I don't know anything about the Vista line, but with it being an older boat (1990 model?) you would be wise to find a boat mechanic to go with you. Be ready to offer them a fee for their service/advise.
If the boat is a 1990 model, I would seriously spend some time trying to figure out if the deck is solid as I suspect they will have a lot of wood in them versus fiberglass. And with the interior not being in good condition, the owner most likely has not done much to protect the decks from water, or to keep water off them (rain).
Like everyone always says, push for a test drive "on the water." Boats can/will run different "on the hose" on land versus in actual water.
Good luck with the viewing and try not to get too enamored with just one boat. Get a few on your list that you really want, then run down a list of Pros/Cons (good/bad) of each. That will lead you to the best purchase.
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1999 180 Horizon OB Fisherman Pkg
San Antonio, TX
Choice of tow vehicle:
'93 Explorer 4x4 (sold)
'05 Grand Cherokee 4x4 w/ 5.7 Hemi (member of the 240k+ mile club!)