If you're a bit stable yourself (& used to skateboard yourself), try long-boarding (4 year old in front of you with plenty of protection, there's enough space o

If you're a bit stable yourself (& used to skateboard yourself), try long-boarding (4 year old in front of you with plenty of protection, there's enough space on a standard longboard to fit an adult & child). Or biking them in a bicycle trailer to the store/school. Surfing is one I'm looking forward to myself, I've never done it either myself!