I am visiting Sitka for a couple of days in early June with my husband and would like to know when is the best time to purchase roundtrip tickets for SEA-SIT? About three months ago, the price was $520, then dropped $200 for about a month, then went back up to $520. Does the price dip during the spring months at all?

Also, we have about 22,000 miles, enough to buy one of our tickets, but we also have the voucher for "2nd passenger flies for $50" that we got from our Alaska Airlines credit card. We have never been to Alaska and don't anticipate making it a regular thing (maybe once every few years). Should we use our miles (we use our UA credit card most frequently to rack up miles) or use the $50 voucher? We live in Houston so Alaska Airlines isn't even an option from our airport.

Thanks!