I would like to use award miles for travel to Anchorage next summer, but there is very little availability. I thought that Anytime Awards were always available?

Also, I can find loads of award availability from ORD to SEA and then from SEA to ANC for the dates I want, but I was told by an agent that this would be 2 awards, they wouldn't piece them together even for the same date of travel.

Can someone help me understand how travel to ANC works? Thanks