For Denver it looks like a morning flight to Anchorage and a redeye return. So the aircraft is based in Anchorage and just does a R/T, not mixed in with the Seattle/Portland flights. One of the longer flights in the system.
Alaska 41
Distance: 2,399 mi | Duration: 5 hours 55 minutes Denver (DEN)-Anchorage (ANC)
Wed, Jul 7 8:00 am-11:55 a.m.
Alaska 42
Distance: 2,399 mi | Duration: 5 hours 15 minutes Anchorage (ANC)-Denver (DEN)
Mon, Jul 12 11:55 pm - 7:10 am + Tue, Jul 13