We personally didn't spend much time in Andenes, just a quick stop to gas up and get groceries after taking the ferry from Senja, but we can see enormous potential the town has—especially if you want to go whale watching (or even on a puffin safari!)
If you're traveling in a camper van (or really any car), Andenes is a hub for doing all your "chores," like filling up the tank, grabbing groceries and wine (there's an actual wine store here), and preparing whatever you'll need for the roadtrip down the island's scenic west coast.
There's also a space center just south of town, where you can learn about rockets and Norway's role in researching the northern lights. We missed it since it was closed for the day, but it looks like it would have been great for the kids!