We drove down to Vik from Reykjavik one day on the single highway connecting the two cities.   The drive itself was more important than the town since the major waterfalls are scattered along the road on the way as well as the edge of a Glacier. There is one waterfall you can walk all the way around it at the bottom so there are great views from the back. (see Video)

Vik itself is not much to look at although they do have black sand beaches for the one day a year you might be able to use them.   We were there in early September and it was pretty chilly.