This is kind of how we did Alaska. Interesting stuff, we booked ahead (although not THIS far ahead) and for many of the stops, we just kinda winged it. At one stop we just got on a bus to Talkeetna ($10 each round trip). It's the town that was an inspiration for the TV program Northern Exposure. The mayor was a cat named Mr Stubbs (now passed, sadly). We visited local artists, went to Nagley's General Store and all around had an amazing day... for $10 each... round trip. So we're leaving lots of ports "open". But there were a few excursions we liked so we booked them 😄