I can't say I've heard of companies requiring 20 hours on type to fly a 210, sounds like b*llsh*t to me. Of the four companies I know of operating 210's (having worked for two), none of them have this requirement, for the simple reason you pointed out - people can't afford to hire a 210 for 20 hrs!
I'd just pack up and get my butt to Broome, Kunnunurra, et al NOW (if you're in the position to do that, otherwise it's gonna be real hard) and make yourself known. As long as you're not too much of a tool you will eventually get a chance to prove yourself, and by the time you've done a check flight, circuits and route checks and they let you loose on your first job you'll probably have close to 20 hrs on type.
Another option is to try n get some skydiving work in a bigger town before you head north or west. It'll probably be in a 206, but it's pretty much the same thing (ok ppl, I know there's a lot of differences but you know what I mean).
Yet another option is to get pals and private hire a plane to hoon around the countryside in. Do weekend trips etc, and if you can fill up the plane it shouldn't be too expensive.
Whatever you do, do not pay some half-*rse company money to fly their flogged out 210!