When we went we took a good pair of hiking boots and a pair of sneakers / running shoes. We used the trails at Alyeska, which are superb, as well as hiked to a glacier which was optional. If you go gold panning than that too was quite muddy on our visit. There is not too much formal dressing in Alaska and if you would be comfortable in a pair of "flats" than have at it. Bring a bunch of clothes that you can layer for the weather swings quite a bit. It truly is wilderness.