Stanley Park
I really really enjoyed this. It was mostly level bike paths along the shore with beautiful scenery. If you are physically capable, I highly recommend biking Stanley Park.
It's about 8 miles of biking.
They have bikes for kids and bikes for two.
You can also take the free shuttle around the park.
TIP # 13: Try to avoid eating at the Boathouse which has great views and good food but is way, wayyy over priced. I liked it but didn't think it was worth what we paid for it