Based on my experience, I would say avoid Douglas County (Castle
Rock/Parker/Highlands Ranch.)
Yes, the job market is competitive, but your level of education
and experience looks promising.
I recommend Littleton, Englewood, Denver Public Schools, and
especially Jefferson County.
I have also found, from personal experience, that the
conventional wisdom - to substitute or accept a part-time job
"to get a foot in the door" - might not be the best advice: Most
districts tend to look as part-timers as only that, and at
substitutes the same way.
The only district, in my experience, that seriously considers
hiring substitutes as full- time teachers is Jefferson County.
Good luck
Posts on this thread, including this one