No slight intended, I assure you. Once you look at it you'll see that about 90% of the module(that is literally not an exaggeration) takes place outdoors, so Cavaliers can excel. As for the rest of the campaign, it's probably more like 75% outdoors. Plenty of space to shine.

Also, if your Cavalier player feels castrated if he or she is not charging, they're not Cavalier-ing correctly. While they shine in this area, they are perfectly capable in more confined environments.