The trunk lock has been addressed above.
Congratulations on a nice car to begin with. As for getting it back on the road, getting the structure solid is a great starting point. Get her up in the air, pull the wheels and rocker covers along the side and look for rust. Check all the usual spots- an awl is an easy tool to use and you will know right away if it is solid or rust-ridden. Check all of the suspension mounting points, especially the rear trailing arm attachment points. Clean as much as you can, maybe a power washer to get all the years of accumulated stuff off the chassis.
Once you know if the chassis is solid, consider dropping the motor and transaxle as 1 unit. That will allow you to assess the engine to see if it seized or turns freely. Great to pull the plugs and squirt some Marvel Mystery Oil or the likes into each cylinder and let it sit for a few days and repeat a few times to loosen up anything in the cylinders before you try to turn it over. If it does turn over smoothly, then move on to valve adjustment, replace all vacuum lines, plugs, cap, points, rotor, air filter, oil/filter, etc.
Drain the transaxle and refill with run of the mill 90 weight gear oil. Don't be tempted to use some fancy, expensive gear oil. Our transaxles perform best with the plain old 90 weight. Check to see if the clutch is free or frozen while the transaxle is out of the car.
If you summit those tasks, now it is time to pull the gas tank and have it boiled out or just replace it as they are available pretty cheaply and that solves a whole host of further problems. I would replace all fuel lines with SS fuel lines and new hoses along with the new filters.
Replace the master cylinder and have all 4 calipers rebuilt - see PMB for excellent work.
Replace the 35 year old tires before you try to drive it down the street. Of course, after 50 years and having sat for 35 years, most of the suspension rubber will be gone or useless. Wheel bearings need to be cleaned, packed and reinstalled, etc.
Clean all of the grounds, front to rear- there a quite a few of them. New battery of course.
The last thing I would worry about is cosmetics. Sure, I would clean the heck out of the entire car, but that is about it until the entire car is sorted and running well.
This will be a fun project and is totally doable if you do it in small bites and stay focused - one project at a time. If the whole car comes apart at once, it is easy for the project to get out of control.
Have fun and enjoy the trip.
Michael