Hello,
Well from my experience so far with the coupe i have simply expect rust ..
Defo check the following for rust.
Both rear arches on mine were completely rotten.
Check the rear gutter make sure that hasn't rotten
Fuel tank as mentioned another good point but often if its only a pin hole or 2 can be fixed.
Also check the front and rear windscreens they often rot when water gets in between the seals can be a complete pig to fix if it has.
Really take your time looking round the car I have found countless holes that were otherwise not visible before purchasing.
As for the car itself yeah mainly would say depending on condition expect a decent amount of welding and body work.
Cant speak for the engine because I am not at the point yet ! xD
I was super worried before purchasing my coupe that i wasnt going to be able to take the challenge on :/
And similar situation to you my first restoration car so was equally as concerned trust me!
But I am 3 years in now and i couldn't be happier or prouder of my purchase .. lots of blood sweat and tears ahaha but well worth it in the end i think
Lots of really helpful people to ask and highly recommend the facebook groups also.
Hope you go ahead with it ! and good luck