No problem, whatever you are up to is fine with me.
Bikes are pretty save around here, my BMW stands in front of my house all year round, and no problems yet. Just take your luggage with you, and no problems.
About the campsites, there are two campsites near the center of Amsterdam:
The first one is on the North side of town just over the canal and is called 'Vliegenbos'. Vliegenbos is a campsite with lots of young people in an small area with lots of trees. You can take the free ferry to the central station (wich is located in the center of Amsterdam). I would advise this camping.
The other campsite is called 'Zeeburg' and located in the East part of town. No experience with this one.
If you are interested i can provide you, and your friend, with a free bed in the center of Amsterdam.
Let me know when you are in town, maybe we can drink a
or go on my friends boat and cruise the canals for a bit...