Child-friendly options?

Hi all,

I'm planning a trip to Iceland -- I've always wanted to go. However, this time I need to bring my wife and 20 month-old son. I've looked at some guidebooks, but there's not much in there about how much one can do with children this young. For example, the hot springs look lovely, but I don't think they would allow children in diapers.

Put simply, my question is whether we are we crazy to consider a trip with a kid this young? Will it just be a trip where he (and thus we) cannot visit some of the best things about Iceland?

Any thoughts would be great -- thanks!

(TLDR: crazy to try visiting with a 20-month old?)