Check the underwater gear. Get behind the boat, on the ground, and look at the rudder, prop, propshaft, and strut. Does everything look straight? Does the propshaft go through more-or-less the middle of the shaft log (where it goes through the hull)?
A good thing to do once in the life of the boat is to align the engine to the propshaft (see attached). This is a gross adjustment that controls how straight the propshaft is. The owner's manual alignment is a fine alignment that needs to be done yearly or so. It'll take you a couple of hours to do the full alignment the first time, so it's a nice afternoon job. Once you've done it, you won't need to do it again unless you run into something.
You might want to consider replacing the strut bearings
while you're at it, and you'll have to re-pack the propshaft stuffing box also. Packing is about $15 for the GFO or $4 if you go for the flax packing, (but it's only good for 15 years or so
), and the strut bearings if you need them are about $70. A quick googling will get you everything you need to know about changing them out, but feel free to ask.
Check the steering. If it's not effortless, consider replacing the steering cable. It's a couple hundred dollars, but a bad one never gets better. Grease the rudder, and any other spots that the owners manual calls out. If you've got extra time, pull the rudder to clean out the old dried grease before doing so. Pull the starter and grease it. Make sure the blower and bilge pump work. Make sure all of the vent hoses going into the bilge are in good shape. Replace the raw water impeller.
Your local dealer, Skidim.com, or GreatLakesSkipper.com are great places to get parts.
By the way, the gasoline isn't a loss - just think of it as lawnmower fuel for the next five years.
Good luck, and keep us up to date.