Depends to some extent on time of year. Jun-Sept, DFW-ANC is a nice long non-transcon leg; in (N. Hemisphere) winter LAX-SJO ditto; the two services don't overlap, and only one ANC R/T permitted, not so with LAX-SJO. Both are in 757s, so an L-class MR would be a pretty miserable experience in those buggies.