Hi and welcome.
Not a complete buyer's guide but start with checking for rust above all else. Carefully inspect for more rust and if it looks good, get underneath and look for rust.
Most parts are available from specialists if you need them.
If the car hasn't been used much and pulls to one side under braking, it is probably a stuck caliper piston.
Vibration from underneath - probably a worn prop UJ or coupling. Neither is expensive.
Rear end steer or a bit of vagueness from the back could be worn trailing arm bushes (again inexpensive parts) or the T-shaped reaction bar's conical bushes (about a tenner a pair IIRC).
Steering should be light and precise. Any heaviness or unresponsive feel, check tyre pressures first, then idler arm or top swivel joints may be seizing, or castor angle is out.
With engine running, inspect rubber carb mountings, lift the bodies a bit and listen for whistling/change in idling speed indicating air leak.
Check front wishbones' spring pans for corrosion.
Push down on the front corner and listen for creaks - if so inner wshbone bushes may have corroded and need changing.
There should be splash panels inside the wheel arches.
Ensure it has a good level of antifreeze/inhibitor in the engine - it's an all alloy engine (block/head) so it is important or corrosion kicks off quick-style if not used.
Check all the usual, oil, brake, fuel leak points.
Good luck - you'll probably be driving one before mine sees the road!