Some former co-workers of mine planned this excellent birding the trip in the valley, and we all had a grand time tooling around, looking at birdies. SNWR is a bit weird, because the primary way of viewing the scads of wintering birds there is to drive a planned circuit and bird from your car. Great way to see A LOT of birds, though, including Bald Eagles, falcons, owls, a bazillion Snow Geese, only a tad fewer Red-tailed Hawks, and pheasants! I had a couple of new-for-me's, including a White-faced Ibis and the Greater White-fronted Goose.
Kind of a haul. I burned 3/4 of a tank of gas in my somewhat fuel-efficient 2002 Corolla, so make sure to start with a full tank. Williams is the last town on I-5 before getting there, and Granzella's is a pretty decent place to grab a sandwich.