Dragon; the Buick Regal was, at the time, the best car General Motors built. If well maintained, it has a lot of life left in it. The intake manifold gaskets were the only significant problem these cars had.
I would just keep driving it and looking after it by the book. Since you drive a lot, it won’t get “bunged up” like so many seniors’ cars that are only driven on short trips.
Elswhere we have a post of a lady who still has her original Ford from the 60s with over 500,000 miles on it.
As my wife says, “Age only matters if you’re wine or cheese”!
Many more miles of Happy Motoring!