The flavor of this side-trek is phenominal. It sets up the party to have a long-lasting relationship that could be quite useful with an NPC that can fit in any campaign setting. While the NPC is not well fleshed out, it doesn't need to be, any DM can handle that task to make the NPC anything they want.
The encounters offer dynamic challenges, not just static combat, they use environmental features well and provide noncombat challenges as well as combat-only solutions.
The monsters are quite good, they follow a reasonable theme and are well suited for level. The only deficiency is that the one elite monster only deals standard damage. It has a few more tricks than a standard, but given that an elite represents two standard monsters, it should have the ability to do damage like two standard monsters beyond the first round. This is easily fixed by any DM.
All in all, this is a very entertaining side-trek that can be used as-is or adapted to anyone's setting with little effort.