It sounds like a nice scooter! If I were to purchase a 15 year old scooter with no idea of the maintenance history I would do as you're suggesting..oil change, coolant change, brake fluid change, gear oil change, spark plug, air filter, new belt and rollers. I would open up the CVT case and clean it up and look at the condition of your clutch pads. They will likely be in good shape with your low kilometers.
Tires are something you'll want to look at. If they are original they are (past) due for replacement. I would also pull the calipers and clean them up and make sure pads are good and make sure your slide pins are lubed and moving freely.
After all this you will have a fantastic scoot in wonderful condition!