If your inbound is late, there are two later nonstops to LAS, plus you can connect to LAS through LAX, SAN, or SNA.
Just remember you will have to reclear security at SFO. UACO is down in T3, WN is in T1. It's about a 10 minute walk or 10 minute train ride (since you go around to parking then one of the the intl terminals).