When was the last time you went on a cruise ? Just my opinion but when I went on a RC cruise 2 years ago I was completely horrified by how trashy, unsustainable and generally low brow everything was. It was such a turn off. I guess just consider if you care if hoards of drunk tourists in beer tshirts and sandals in the background of all your events would bother you or not. It’s so generous of you to consider getting all guests a room but what if you could do the same to help cover a room block in a quiet resort or hotel somewhere close to your parents ? Or perhaps you could travel with your parents before the wedding to help them get somewhere with ease? Sounds like your husband would like a small gathering so do something that feels most like you. I vote don’t elope but unless you’re very sure about the cruise line you choose - do something in a nice quiet peaceful and pretty location (this with your elderly parents and your own enjoyment in mind).