From another mailing list to which I'm subscribed, a pointer to a
discussion of how far you can go on public transit within California. Someone managed to figure out this routing to get from Los Angeles to the Bay Area completely on public transit buses and trains (no Greyhound, no Amtrak).
( You'd have to be crazy to try it, of course )Mind you, this routing won't really work unless you factor in overnight stays at several points along the way due to the mismatches of the schedules. I haven't tried to work it out myself, but at a rough guess I expect at least two overnights would be involved, maybe three. Not to mention that just the accumulated fares are more than the cost of a one-way ticket on Southwest Airlines.
This does remind me that during the glory days of the interurban railways, it was said to be at least theoretically possible to travel from Chicago to New York City totally by interurban, without resort to the "steam railway." Except that, just like the routing above, you couldn't do it without spending the night somewhere, be it a hotel or a lonely interurban stop.