My husband proposed on a cruise via an excursion. It was via a helicopter that we took to a glacier (from Juneau - Herbert Glacier). It was stunning and unexpected. The pilot captured the moment and then there was champagne and the stunning flight back to port. I would highly recommend doing something like that - helicopter to tour, factor in a stop somewhere beautiful, pop the question, toast....and then return. Make sure if you do this you let the concierge know and schedule to have champagne or similar in your cabin upon your return. We did (it was Celebrity) and the captain heard about it, so the champagne was upgraded and a nice note left from the captain as well. Best day of my life until then!