+1 on rhubarb. this will be your first harvest in coming years, not including the greens you've overwintered.
what kills asparagus on the west side is too much rain.
plant crowns, about 3-4 per person you want to feed. It'll take at least 3 years to get reliable harvests.

cover the patch for winter, but water occasionally.

Stam, why alfalfa? If your ground needs organic matter, wouldn't bagged compost be better?
I've just seen my ground not be productive when adding a bunch of uncomposted green or brown stuff. Takes a year or more for that to break down.
I'm actually paying $200 for a "permaculture" dude to come out and tweak my plan a bit so I can harvest something year round.

now you need a root cellar, pressure canner, and wheat grinder, home drilled well with 12v pump...
you'll have all the modern preppers current faves.