Just stumbled on this thread....
I was fortunate enough to crew on some of Apollo Airways' Jetstreams in the early 1980s, and having fond memories of them, these photos were really a blessing to see! There don't seem to be that many quality photos of Jetstream airliners out there in Google-land.
What Graham says about the max weight being a detractor is correct.
Apollo ran service throughout California for several years but maintenance costs and the gross weight limitation under FAR135 rules kept them from being very profitable. The Astazou engines were problematic in that they had low times-between-overhaul, and seemed to be the limiting factor in the airplane's reliability. From a passenger's point of view the airplanes had balky air conditioning/pressurization, an annoying wing spar in the aisle that caused quite a few to stumble, and the cabin was VERY noisy. I have to attribute some of my hearing loss to the 3,000 hours I logged in it, in spite of foam earplugs covered by David Clarke headsets. But the Jetstream was fun to fly and had great performance.
I built an Airfix kit back in the 80s and made my Astazou forward engine nacelles and gearbox areas from plastic tube, which was thick enough that I was able to chuck it in an electric drill and shape the intake lip against a hobby knife edge. The nacelles were faired into the Airfix kit without too much fuss, while the little bumps and strakes on the nacelles were made from scrap plastic.
I'd like to build another kit as N5VH pictured above in Rob's post. This green and gold trimmed Jetstream was used in the opening scenes of "Moonraker" (where 007 is thrown out of the airplane) and later repainted in the standard blue and red scheme with different registration. I'll probably use the Airfix kit again since I like the fuselage shapes slightly better than the Amodel, and am in the process of designing an Apollo Airways decal for Greg Drawbaugh (drawdecal.com) for his decal e-store.
Thanks to all who posted photos and info I hadn't seen before. I haven't yet figured out how to post my Flickr photos but will try to do so in the future.