What are the specs of your computers, Dwight and Peter? I've always had low frame rates in FSX. Even now, with a fairly high end laptop built years after FSX was released, I see the frame rate drop to 10-15fps in large cities. And I imagine Prepar3D will be even more demanding.
FS hound here also from FS2000 onwards.
Sadly, my ex trashed all my gear and media, so I do not have it on my current PC.
Last version I had was ACOF, and I bought so many add-ons, also sadly lost to she who shall not be named.
Yes I would go for a virtual airline, but my dearly ex-beloved broke up the gear and destroyed the disks.
I very much liked the cold and dark start-ups, where you had to do everything, including the programming of the FMC.
ETA: Right down to smashing the joysticks FFS.