River Cruise Bike Tours in Netherlands/Belgium

Next month, my husband and I are going on an AMA Waterways river cruise to the Netherlands and Belgium ("Tulip Time"), and there are several bike tours offered, but we can only do 2 and don't know what to choose.

We are both 42 years old and exercise regularly, but neither of us are bikers (haven't been on a bike since we were kids). We are physically fit and don't mind a challenge, but we aren't looking to kill ourselves on these tours either--we're looking for a fun way to see these locations and aren't mad about getting in some physical activity at the same time. That said, some of the tours are listed as "level 5," but we also know that we will likely be on the lower end of the AMA Waterways clientele in terms of age, so we aren't sure how hard a "level 5" tour will be. If anyone has any insight based on past experience, we'd greatly appreciate it.

We're also interested in hearing general thoughts on bike tours in each of these locations if anyone has done them/similar bike tours before. Our options include:

• Kampen - Level 4, 9 miles, 2 1/4 hours
• Bruinisse (Zeeland) - Level 4-5, 16 miles, 2.5 hours
• Antwerp - Level 5, 5 miles, 2 hours
• Kinderdijk (Dordrecht) - Level 5, 6 miles, 2 hours

Any thoughts would be greatly appreciated!