Oh. I thought you were using the USDA zones instead of the Sunset zones.
In that case, your list of potential outdoor growers will probably be entirely limited to terrestrials. Not sure if any epiphytic orchids will survive an average lowest temperature of 28F and an average highest temperature of 95F. Quite a few
epiphytic orchids would survive that temperature range...if it wasn't average temperatures. If there are any that could take it, you'd probably have to water them every day during summer...which isn't unreasonable if you set up an
overhead misting/sprinkler system.
If you don't mind experimenting you could try a Laelia anceps.
There aren't any orchid nurseries in Lancaster that I know of. The closest orchid nurseries are in Santa Barbara and San Diego. However, there are numerous online
orchid nurseries to select from.
I'm not familiar with terrestrials so hopefully some other folks will be able to chime in.