The 200 used to have a separate co pilot (second class) type rating until the then CAA (sometime in early to mid ninties) made it into a command type rating with no distinction regarding co pilots.
As far as time in the right hand seat of one of these types goes. Don't stay there too long. However, as long as the operation you work for has set out in its' ops manual, approved multi crew proceedures, then you could be flying a 737 for all anyone cares. It's multi crew and that in itself is good time to have if you want to progress to the regionals or airlines, and they do take it into consideration.
In Australia, correct me if i'm wrong, if your aircraft carries more than 9 pax on charter or RPT then you are required to operate with 2 pilots. That means 2 crew SOPs in the company ops manual. The 200s have been known to carry up to 13 pax + 2 pilots in a high capacity config. So regardless of whether or not the AFM says it's a single pilot aircraft or not makes no difference when you are logging legitimate co pilot time in accordance with requirements that are set down in the regulations.
Decent Multi crew procedures can be applied to any type of aircraft within reason and used very effectively.
On a side note, metros can and are often flown single pilot just like the King Air.
Good luck and have fun.