I will be the first to say CONGRATS ON THE NEW BABY!! With all that is new to you and the little kid, a ride even to a hotel on the bike for some much needed sleep will be a good thing. HA!!! As for a route, well that comes in to play with what you want to see and the ideas of those who have offered opnions here already. I will throw in, if you need a night to crash around the Seattle area, let me know. My now 2yr old won't mind as she sleeps now throughout the night.
What I might offer as a recent dad this past two years is to figure a route as big as possible, yet, if wife or yourself has an incling to have you home soon, you are within a SOLID LONG (1000 or so miles) day ride back. This is just a thought in case something should or would come up even with inlaws there, heavens knows it is a good thing to be out of the house when they are around. Mine only live 5 miles away, so i am left with visits often and endless bags of crap to leave behind.
Anyway back to the route!! Anything would be good, you can meet some great people along the way and see some great stuff. Let me know if you are near, as I can stuff soem food down your pipe and wash it down with a beverage of choice.
Jeff