Southwest Travel in Sept/October
I don't know about that area, but most towns /chambers of commerce/ tourist agencies have web sites and litterature galore. Pick a destination, put it in a search engine and there will usually be some useful links. Also if there is a particular type of activity you enjoy, try looking that up to see when it takes place where. If all else fails, call the town or city hall. If they don't have the info you want, they should know who does.
Hope this helps!