Just had a day and a half trip to KTN - its a nice town to visit, especially since it was sunny ^
Some interesting parts to walk- and easy public transportation with the bus. You can take the bus all-day for $2
Take the Blue route south and it goes right through a totem park on the way back. I didn't make it anywhere north of the airport ferry...also an interesting sight- as there is no bridge to KTN.
JNU also has a decent bus system that can take you to the Alaskan Brewing Company who has free tastings ^^ Its also near a micro-Costco...
[nothing too exciting there though]