1982 Cabrio Restoration

I've reached the stage where I have to decide how best to treat the ageing areas of my Cabrio, now that I have it on a rollover jig.  Generally the cabby is sound but has superficial rust in quite a few areas.  Where the wheel well joins to the rear valance is the worst place for rust, as well as around the rear towing eye.  I don't wish to strip off everything underneath but prefer to concentrate on the obviously exposed areas, as I think the existing rust protection treatment has been done very well and should last.  Also as I have decided to replace the rear drum brakes with discs, I'll replace the hydraulics lines at the same time.
It's odd that the floor below the driver's seat has significant rust.  How did that happen?  Maybe a leak from below?
I'd be interested in people's comments as to how far they think a restoration should be taken.  Personally I'm after mechanical reliability first and foremost as well as a solid structure.  I don't want to restore areas just for the sake of it.  What do you think?!

All about how deep your pockets are, if your already that far in May as well go the full month 👌 

Thanks for the comment.  I've already spent much more than I originally expected, (and more than I paid for the car in the first place!), but that's par for the course in this game.  I don't expect at all at the end of the process, to have a car with a sale value that's anyway near my expenditure.  I'm guessing I'll have spent roughly four times as much as the original purchase price.  What I am hoping for is reliability good enough to undertake long journeys without fear of breakdown.  At the end of these main repair works, I still have to face up to a full hood and insulation liner replacement.

Yea it's pretty cheep to pick these cars up now, mine cost me £1000in pretty good nick , although I'm close to spending 2k on it , unless your going for a show car I doubt you will get back what you put in ,  as long as there is no rot then it should be fine , engine wise just keep it all simple , keep it serviced ect, 
I've just priced up full hood replacement and there no change from £1000 if you do it right and to last , 😔 
But like you said , it's more a hobbie haha 

It looks pretty solid from your photos