Look up the routes in the back of the AFD. If your exact
destination/origin isn't there, try and figure out what the most
likely route is based on nearby airports. Or access the FAA route
database on-line (http://tinyurl.com/8w2l). It's always nice to hear
"cleared as filed".
I have done both of those, with middling success. The route database
seems rather sparse. For example, it's not got a lot of low altitude
California to California dep/dest pairs other than SFO/LAX.
I do remember there was a website for the old Bay Approach which had a
lot of preferred local and TEC routings. Can=B4t find it.
Avweb has an article about this, too:
http://tinyurl.com/6k25m
dave j