I know speaking for myself in 2 similar situations, i had a 1984
H/O and a 1984 Buick Regal T-Type all original that i had this same dilemma, In fact mine were perfectly running cars that had some minor rust issues, and i didn't want to get buried in too deep into body work, AND i don't tolerate any rust on my vehicles. Its very easy to sink loads of money into a car that's not worth it. In my case i stripped all the exceptional parts from them, interiors, drive trains body panels ect ect and junked the rest. that's just my own experience, and what I chose to do, weather it was right or wrong, I will leave that conversation closed. If it were me I would sell the regal you have or part it out to those who could use some of the parts, put the money back into your current ride your keeping.