Hi. after reading the fantastic advice on Flyertalk I'm trying to come up with a plan to get my family of 4 to Europe (anywhere) from YVR (home) or SEA. About me: infrequent flyer (5-6 leisure flights/year), 40K Aeroplan points in my account, rest of family 10K each. Plan: in 3 years want to fly all of us in the front of the plane with a couple of stop overs and open-jaw. Are my assumptions correct:

1) SEA departure (instead of YVR) with UA due to huge savings on fees ($300 per ticket vs. $800)
2) Will need to accumulate about 400K miles, and all in my account is ok?
3) Currently Have no AP CC - should sign up for an AMEX, Canadian AP CC and SPG card NOW to grab the bonuses and start accumulating AP miles?
4) AC/UA/Star Alliance is my best bet to do this?
5) Current CCs - Alaska, Capital One MC

Any advice would be greatly appreciated!