As she's a dressmaking instructor and historic pattern designer, she's done some great research. If you visit her Sewing Academy Compendium, you can find information on how to dress like a Pioneer in warm and cold weather:
- Girls - For an example of what I've made with her patterns, click here or here.
- Women - For an example of what I've made with her patterns, click here or here.
The patterns/companies listed on my patterns for purchase link also seem to be historically accurate, but then you have to buy the pattern to see what they have to say!
Additionally, The Workwoman's Guide, which I found on Google books, is a book published in 1840 by "A Lady." It is pretty hard for me to understand a lot of the sewing terminology, but it gives patterns for how to make tons of stuff.
Westville has some quick guidelines on dress for both men and women.
Costume of the California Goldrush seems to have some good stuff, too.