Not the best bang for your buck, but the fares from BCN/MAD to LAX/SFO via AMS/CDG are still available until End of season.
That would net 90 XP for €1300. As I said, not the best bang for your buck,
but that’s at least long-haul

. Shortest days between arrival and departure seems to be 4 days, with at least one Sunday.
Exemple fare:
https://www.google.com/travel/flights/s/bcDx
If you are Paris-based, a CDG-MAD in J will set you at €360 R/T, €12/XP.
So if you do from CDG pre/post run in J as well, the whole trip sets you at €1,660 for 120 XP, @€13.83/XP
You’ll notice SEA is also available, but be aware that SEA is considered Long 2, not Long 3.
On the menu today, may I also suggest, for a good’ol EU J run, a LIS-KRK available this summer at €490 with a double stopover CDG/AMS for 90XP, doable on a Saturday/Sunday with a PCR test done Friday morning, yielding a pretty decent (by today’s standards) €5.44/XP (exemple fare:
https://www.google.com/travel/flights/s/gS4Q - the price shows 550, but dropped to €490 when I booked it on AF PT )