As a practical matter on airfares: it's a soft market right now, and you can get next-day airfares between boston and SF for mid-200s each way, which is barely worse than booking a month out. Doesn't seem like grounds to wait. (As I write this on Wednesday morning: Thursday, SFO-BOS, 7am-5:52pm, DL5831/DL2534, $259 including taxes.)