The area around Shanghai is a vast crowded delta with low lands close to sea level. When it is not built, it is rice fields, rivers or ponds.

You will find few spots where you can set up a tent but they will be certainly full of rubbish.

Also if security is one of your concerns better to stay in an hotel where you can park your bike.

Regarding the hotels, you can find some very cheap places. It's called hotel but it is more few rooms on the back or above a shop.