It's been a while since I've been to Guaymas but I have friends who have been there recently and while it does have its charms I would not say that
it is really a tourist town. As the other poster has mentioned, the area of interest to tourists is really the town of San Carlos which is about 15-20 north of Guaymas. It is a beach town which is very charming. A lot of spring breakers were going there but since there has been an issue of safety in certain parts of Mexico, I think this has decreased the number of tourists there. There are some very nice resorts there. In fact the location is so picturesque that club med used to have a property there in the 80's and I think into the early part of the 90's.