Welcome from MA!
Don't assume everything needs to be replaced, just because of the overall mileage and age. There may have been some things already replaced. Someone may have already beat you to replacing water pump, fuel pump, whatever... Don't assume everything is old and ready to fail.
Start with the fluid changes and vac leak as already mentioned.
Age and condition of the battery?
You'll want to inspect immediate safety items and replace if needed...
Brake pads - check for wear/damage
Brake rotors - check for warpage/wear/damage
Brake calipers - Pistons move freely? Any leaks/damage? Caliper moves free on the slide pins?
Brake hoses - Any visible cracks/leaks/damage?
Inspect hubs for play - Do they move or clunk when you try to wiggle up/down/side to side?
If there is any slop, replace them ASAP. New hubs come with new ABS sensors. Get a quality hub assembly and be done with them. If you see ABS lights, there is a good chance that might be caused by excess slop in the hub. New hub takes care of ABS sensor issue too.
Inspect radiator and heater hoses - Any cracks? Are they hard?
It has been mentioned on other threads, but put on your list sooner than later... The plastic "T" quick connectors that hook up the heater hoses to the heater core in/out fittings. GM parts if you can get them, Dorman if you must.
Either way, you'll want to know the plastic fittings will not just break off on the road like mine did. I was lucky, I was close to help from home and a NAPA was 2 miles down the street. An easy job, but would have been much quicker if it were in my driveway rather than the parking lot of my barber shop.
Clean all ground connections to the engine, body and frame. There are several and they are critical for everything to function properly and not drive you batty!
Replace critical safety items and see how things are after that.