I feel like they're too soon for marriage, or even a proposal. They've been in this off-and-on, undefined place this season, and that's not a place you start a marriage from. I think Calleigh especially is way more cautious than that, and would need to have been in a relationship for a while before she'd say yes to a proposal. My guess is this season we'll have them finally decide they really want to be together in a serious, committed relationship. Maybe, maybe they'll move in together, but I can't see it going further than that right now.