I've never smoked with my parents, but I doubt they'd say no if I offered. They too are old hippies, and while I don't think they still smoke, they'd smoke with me if I provided-- I think.

As a son about your daughter's age, all I can say is this: be open with her about your past and trust her to make the decisions that are right for her. Don't pressure her to either smoke or not smoke, and just make sure that she understands the concept of responsible use-- of anything. And hell, if she wants a safe smoking environment, there's nothing better than smoking with your parents, right?