I'd definitely go E to W so that you're starting in the SE and aren't crossing the W mountains until late-March or later.

These sorts of adventures always hinge on how dedicated you are and how much you're willing to roll with the punch on timing. If you love challenges, are willing to endure considerable hardship, don't mind taking (some would say stupid) risk, and have enough time to hunker down for a patch of bad weather, it can be done. But if your motivation is simply that you're an average bicycle tourist who can't get the summer free, I'd wait until you can get a summer free.

There is no magic route that makes an infeasible trip feasible. The key is to avoid elevation as any route that gets above a thousand feet or so will be subject to snow, ice, and freezing temps in Feb and Mar. Once you get past Texas, your options to stay low diminsh so you need to watch weather closely and be willing to wait out bad weather. Unless you're really hard core and/or have a lot of schedule flexibility, I can't see any way to cross W TX, NM, AZ, and CA in late-March/April that isn't down in the I-10 and I-8 corridor..... tackling high passes at this time of year would be foolish.

- Mark