The rental location is a hut to the east side of the main building, where they also rent beach umbrellas and lawn chairs. They have different kinds of bicycles; the one I rented could fit two adults (officially three but that'd be tight) and two children in special child seats in the front. They also have a two-row version that can seat up to six adults, plus possibly other styles.
The price was very affordable - $20/hr in my case. We ended up not even using the whole hour because after a while my kid wanted to go on the beach instead.
The bikes are great! Steers and drives well, though pedaling can get tough; fortunately multiple people can pedal, which definitely helps!
I've lived in the area for four years and regret that it took me this long to get here; but no worries, I'll definitely be back when I can!