Educate me on T/C Contenders

[DiverDn]

I'm thinking of buying a Contender, I don't want an Encore because I want to be able to shoot rimfire and as I understand it the Encore does not have the hammer to shoot rimfire.

My understanding is that between the original and the G2 the differences have to do with cocking and re-cocking. On the original you have to work the action in order to re-cock once you let the hammer down, on the G2 you can de-cock and re-cock without opening the action. Also I think I read something about a transfer bar safety.

What other differences are there between the original and the latest version?

When looking at older used guns what should you look out for? Or are they pretty much indestructible?

How difficult is it to do trigger work on a Contender?