Some cruise lines offer an excursion when you are visiting glaciers, a smaller boat picks you up from the ship and takes you closer to the glacier. We've done this a couple of times and both times the ship dropped us off at the Glacier (via smaller boat) then the smaller boat caught up with the ship again in Juneau. Not the cheapest excursion, but we felt it was well worth it. The smaller boat has inside seating as well as outside viewing decks. We got a lot closer to the glacier than the ship could, plus we saw seals and whales on our journey to Juneau. The only walking required was a rocky gangway to board the smaller boat, so not sure if that would be an issue.