The island of Gotland is pretty small if you are driving.
We decided to just sleep in Visby though.
Zok and I were out of our element though, and I think we could not fully appreciate the island. There are many ruins. Visby itself is a walled city (not as pretty to my opinion as Chester). The wall still has over forty towers, and is a UNESCO World Heritage site. The wall unlike Chester can not be walked upon. The whole thing is about 4 kilometers. The churches have parts that are from the 1200s, our hotel had parts from the 14th century.
The ruins are older than that. This is not a time in history that I am knowledgeable of- so most of my reading ending in my thinking 'Gee that is old'.
As we were there at the very end of August, even the museums were closed. We did stop as some Viking areas, stone markers, ring stones ala Stonehenge. But Zok was really focused on his 'Loppis' quest.
No road sign was too small to go off road for a look.