The Crown Victoria is quite pleasant to work on in general, although changing the rear spark plugs on my '86 was a huge pain--not as bad as a transverse V6, though!
Physically large car, so there is plenty of room to get in and out to work.
Body on Frame instead of unibody construction, so damaged body panels are easy to change out.
Unchanging Design: the final body design was originated in 1992 on the Grand Marquis, and is otherwise unchanged.
It has a small block V8 and it's a dream to work on any bolt-on component, unlike most newer vehicles.