It won't be easy or cheap. 42s have a cult following these days, and the prices have risen like the Model 12s.
Pros, they last forever, like the 12.
Cons, they're 410s and some are 2 1/2" shells only.
I'd keep an eye on the bulletin boards at your local ranges,etc. Forget gun shows, a show special these days means an inflated price.
And check out the Browning 42. It's not quite the same, but it's nice.