Check out Heavenly for this one:
It has a run called Gunbarrel and to get to it, you must take a lift (Gunbarrel express).
You could also get there via Aerial Tramway, however the clue states "lift", so I am assuming its the first one.
As far as Wagon Train-check this site out: there is an annual wagon train that goes through South Lake Tahoe (which is what you will see if you are looking down gunbarrel)
Here is a link:
http://co.el-dorado.ca.us/stories/wagon_train_2002.html
Big valley is the whole Lake Tahoe area.
This is what I am putting down :)