Spent a few days in Strasbourg 1 1/2 weeks ago. The cathedral is awesome. There is a light show each evening outside the cathedral - a delightful, unexpected event for us. No need for a bike. Agree with others walking is sufficient. There is a tram from the airport that runs through the downtown corridor. Convenient to get to and from airport to Petite France.
If there is no change is weather, it is very warm in Strasbourg. We made the mistake reserving hotel with no air conditioning (which is not hard to do since most hotels are quaint, charming and historic. Being there for one night, this may not be an issue; however even one night's sleep in heat with no air may be challenging.
Canal ride was nice - I would recommend. You can buy tickets on-line. Tourist office, next to Cathedral, is awesome! They gave us lots of suggestions, directions and maps. Great wine shop around the corner from tourist office as well!