The only way from Angoon Harbor to Bellingham Harbor is by ferry. You should expect to be able to find tickets starting around $320, if you search flights from Angoon Harbor to Bellingham Harbor. Ferry from Angoon Harbor to Bellingham Harbor, it will get you there soon enough!
For these medium length trips, it's important to book your tickets as soon as possible. While there are ferry transportation options available, the sooner to book the better. While prices for buses or trains might not fluctuate as much as flights, their availability certainly will. It's recommended to book these flights at least 2 weeks away, but even more if you are able.