That camera looks very promising, and I have some Pentax lenses. I can't find any on KEH, though.Pentax made the *ist (film version). It's small and light in weight. It's a very simple camera for amateurs.
What models are you thinking of? It's hard to get a sense of size/weight when buying online, like I did with my F4.There are similar models from Nikon, Canon and Minolta (later Konica Minolta) on the used market that should fit the bill.