There are a lot of cool things to check out in Juneau.
There are a couple of food truck parks. One in the valley called Vintage Food Truck Park and one downtown. Both parks have a Crepe Escape which serves crepes filled with stuff wrapped up like a sandwich taco thing. Also deckhand Dave's sells fish tacos and fresh oysters.
Heard they closed down, don't know for certain. Would be a real loss.
Pel Meni's is open. It is good, and is always discussed when someone asks this type of question. Not sure why it's the famous Juneau cuisine though. Check it out.
You can drive to the glacier. I don't think there are that many places in the world where you can do that.
Mount Juneau or Mount Roberts, both accessed from the Basin Road/Perseverance Trail area are good day hikes if you want to get on top of a mountain. You can take a tram to the top of Roberts if you want to skip the exercise. Mount Jumbo trailhead on Douglas is also a pretty accessible trailhead, and an awesome hike. I'd probably recommend Jumbo for a mountain climb if you were going to go for it. Can be done in a day no problem.
There are a lot of great trails in Juneau. The Airport Dike Trail, Perseverance Trail, Rainforest Trail, East Glacier Trail, West Glacier Trail, Eagle Glacier Trail... Let me know how adventurous you want to get and I'll make a recommendation.
A boat trip to Tracy Arm Fjord is pretty cool. There are a ton of glaciers in there, and the scenery is really spectacular. It's a few hours round trip and there are a couple of tour companies that go in there.
Flight seeing is cool. You can do a fly around with Wings of Alaska. They will fly you over the top of a couple glaciers. Or they will take you to Taku Glacier Lodge where they will feed you some salmon before bringing you back.
You can charter fish. I've never done it, but there are a lot of operations. I can ask around if you want a recommendation.
The cruise ship industry is insane. There are often six ships in Juneau. So, I'd avoid the downtown/tourist trap thing if you don't like people. It's honestly not that big of an area, and really not that bad. It is just a bit of a zoo sometimes. You will not be able to avoid the people if you do any of the tours that I mentioned.
Bring a rain jacket. It's been a rainy b*stard this summer.
There are hotels and airbnbs and whatnot as places to stay. What kind of thing are you looking for?