Until a couple of years ago, California TEC was published in the chart supplement only in southern CA. Now, it's also published for northern CA. I know, I know... lots of folks would insist it existed up here, but I'm only citing what was in the chart supplement.
I've done training in SOCAL and it was easy to go places IFR. Just call up ground and ask for Tower Enroute such and such place. No need to pre-file. I tried it up here in NORCAL (after TEC was published in the chart supplement) and got "say again? what are you asking?!" After I got a chance to talk with the tower controllers (a couple times at different facilities) and was told they don't have the coordination that SOCAL has to do what they do. So, just file as normal and get a clearance as usual. So, other than having a big hint about the route, there's not a big difference from a pilot perspective.
Having said that, and before others chime in insisting they can get tower enroute, yes - I've asked nicely and got tower to file a route for me. But, it was time-permitting and they were doing me a favor.
