https://www.hurtigruten.co.uk
has a link "Norway port to port".
For example
https://www.hurtigruten.co.uk/port-to-port/?fromPort=AES&toPort=TRD
then you can select cabins, meals, etc, and proceed to payment.
(I went as far as the payment page, did not pay)
Make sure you click 'no thanks' (or yes, if you really want it) to dismiss the newsletter signup overlay at the bottom of the screen, because it covers the button to proceed to the next step on some pages. I only see availability up to 1 April. I suggest you look in a month or two's time.