Mid-March riding between Chicago and Seattle?

In a couple weeks I'm driving from Chicago, IL to Seattle, WA. I'm hoping to be able to ride somewhere along the way. Anyone know of any place that won't be under snow in mid-March between the two? Possible routes include: I-94 & I-90, I-90, or I-80 & I-90. I would not be opposed to cutting into southern Idaho or Oregon if the conditions wou;d allow for a good ride.

I realize all the states I'm driving through are in the north, and that the further you get from the equator the colder it gets. Wishful thinking here, I guess.