Yep patience is the key. I think a lot of people forget that work is being done all the time, whether we see it or not. Unless you physically go to every site, you won't know what's in progress. They go to whatever site that's ready for work, regardless of where it's at.
Here, as in Ventura? There's already one site in Oxnard and a few in Ventura complete, although 3G only. I know the one near my work is waiting on fiber from ATT still. I'm guessing the others that aren't live with LTE yet are waiting on backhaul as well.
A page or 2 back I posted some pictures of sites...if you see antennas or RRU's up that look like that, you know work is being done on the site. Here's a guide on what to look for, with lots of good pictures: http://s4gru.com/index.php?/topic/3915-how-to-spot-sprint-antennas-and-rrus-alcatel-lucent-style/