Hi there. Nice to see meet another "stubborn" 240sx owner with an original, instead of another "build".
Don't be too disappointed if the kids don't want to get involved
The biggest problem is going to be ....plastics and rubber and leaks.
Since it's been sitting for so long.
Check the fuel lines coming out of the tank, - there is an access port from the hatch - and into the engine compartments. Especially the one you can't see under the fuel filter. They get soft, so don't wait until there is a gas puddle under your tank
Replace them along with the fuel filter.
As far as suspension goes, I replaced shocks and struts around 100K with KYB and didn't notice a difference.
Replacing inner and outer tie rods though brought back a nice solid steering wheel feel.
And don't forget to throw some wax on the clearcoat !
Enjoy !