SMF and SJC are often very cheap from both LGA and JFK

you can stretch LGA routings to over 3000 miles each way by routing via IAH
similar story for LAX/SFO connections out of JFK

i saw these for as low as $242 round trip same day turns recently, they're my "go to" from this coast for a quick 5500-6000 miles.

another outside the box option are the one way fares that have been available recently from Caribbean to Hawaii in first class, you could do a circle trip that way and knock it out and get to visit a couple of good destinations along the way on a long weekend.