I'd suggest a couple of first-person accounts. All should be available from used book sources online:
Emily The Diary of a Hard-Worked Woman , by Emily French. It's from 1890, a bit later than the "first wave" of Colorado settlement, but shows just how terrible conditions could be for a divorced woman in that era and region.
Mollie, The Journal of Mollie Dorsey Sanford in Nebraska and Colorado Territories 1857-1866 Probably exactly what you're looking for.
I'd also recommend: