My wife & I have flown up to be with our son & his family. We have gotten to do some exploring & camping with them while visiting.
:C Clicky :C for a few photos & report of these trips.
We haven't gone to Seward yet, but they have cruses out from their, as well as Whittier to see glaciers & wildlife. From Seward, they go to larger ones.
We enjoyed a day cruise on the Prince William Sound (really a Fjord) from the port of Whittier. The food was great. Our son & family have also gone on one from Seward.
Perhaps a trip to Denali (entrance) by train would work (however, slower than to drive it). One can use the trains to go to Whittier & Seward as well.