Having bought another boat that was sitting for over a year, here's the things I found out the hard way:
1) Change the fuel water separator filter and any other filters. Even with the gas removed, they gunk up and who knows when they were last changed.
2) Make sure the outdrive oil and engine oil/filter are changed and new.
3) Given it's a '97, my guess is it has a 4bbl carb. Good chance the carb will need a good cleaning. Get a good carb cleaner, spray down the outside to make sure all parts move freely. Once you get the boat running, spray out the throttle body.
4) It doesn't hurt to replace the plugs, wires and distributor parts.
5) If you're going to start it out of the water, make sure you have a strong water flow through the muffs and the outdrive is down.
6) Oh yeah - charge the batteries and see if they hold the charge. Make sure the battery connections are clean.
7) Grease all the points that you can see. They don't require a lot of grease, usually a couple of pumps.
8) Look at the fuses and connections. Clean any rot, etc.
9) The hydraulics should be at the fill level.
10) Give the hull (above the water line) a good cleaning and wax. Don't wax below the waterline as it does actually work opposite of what you make think.
11) When you put gas in - also use a good stabilizer with the E-10 mixture unless you're filling from a marina that already adds it. They have to tell you if they do (at least where I am they do in NH).
I'm sure there's more. A good cleaning. CONDITION the vinyl after cleaning. It makes a huge difference.
Good luck!