Look for rust, carefully. They always rust...feel around the floors for soft spots as the undercoating might not be damaged but no metal on the other side. Look around the frame areas, under the back window, rockers, jack points.
Power windows are never a big deal, but the parts are expensive-usually a striped tooth on the lifter (scissor type set up). Check for power first, the switch has to be hooked up in the door.
Cruise almost never works, again parts are expensive. It is a fairly simple system with lots of online diagrams/how to's. Run through all the steps before assuming it is one part, test everything!
Tach again almost never works on these old beasts, not so expensive and very simple just a pick up, amplifier and gage. In my experience used parts from either the cruise control or tach seldom worked, it was a weak spot on these cars so deal with rebuilt or new stuff to save grief.
Sunroof is likely dried up, some lube should help. The cables run all the way into the trunk, you need someone that understands the system before you tackle it, pull the cables, clean, and possible lube not sure what to use do a bit of research. Grease the slides and contact points in the roof where parts move. This can be a big job (a few hours) and def not everyones cup of tea.
Enjoy the car, ours has been in the family since 1986, love it. Things to improve, tires/size the 14" is overwhelmed! Headlights, either euro or conversion small round lights.
Grab any spare parts you can find, they are getting very rare to find.
Consider a manual climate control (European) when the auto dies, it is full of expensive parts.