Consider getting the Alaska Airlines Visa signature card - you get a $99 companion fare (plus applicable taxes) on any fare - so you pay 1x full F, and the second ticket should run you about $150 total. All the travel has to be on AS, so that probably means driving to AUS or getting there some other way.

The AS F cabin isn't luxurious or overly comfortable, but it is ok domestic F, with usually very friendly service. I don't know how good/bad the connections are through SEA but you can probably do the trip for under 2K for the 2 tickets with the discount code. It books in full F and you both get full F mileage accrual.

Note - I'm not sure if you have to bank your miles with AS when using the coupon. (Otherwise, you can put them @ AA). Also, AS F gives you lounge access @ SEA when booked in full F.