B6 778 then WN 1590 at Boston
Las Vegas → Boston → Denver
Timetable, Boston time
05:00B6 778 from Las Vegas at the gate
17:10WN 1590 to Denver leaves the gate
12 h 10 apart on the timetable
WN 1590 leaves 12 h 10 after B6 778 arrives on the timetable: more than half a day, so not a connection we count.