Snacks With Drinks
It's usual to be given some sort of snack with your drinks. This is usually just a bowl of nuts or olives but can be more. At Cafe Central we got a bowl of mixed nuts and a bowl of marinaded raw vegetables (shown). It was almost a meal in itself.
The Ancient Agora makes a great ready-made picnic spot. We often bough lunch (from the bakery mentioned above) and went to eat it in the Agora. There's lots of rocks and grass to sit on, and shady trees to sit under. If you lucky you'll find a few cats wandering around too who will enjoy the odd titbit from you. Cakes!!
The outer walls of the castle are pretty thick, as you can see from this picture. A variety of such lookout points give great views over the harbour and the sea across to Turkey (I guess that was a big concern in the Knight's day) as well as providing countless photo opportunities for today's visitors.
Not a quiet Aegean vacation spot
If you're aiming at having a quiet vacation relaxing by a nice beach during the day and strolling around in the evening, and/or to experience some greek culture Kos is not the place to go. It's different if you're a young European tourist whose travel priority is to party and get intoxicated every night. The foreign (dutch, chinese, etc.) restaurants and bars look completely out of place. The noise levels in the main town are quite high all the time and they come from cars, motorcycles, TVs, sound systems from bars and restaurants. Everything revolves around tourism most often in a taste-less manner with a lack of local character, unfortunately.
"Beaches - not great"
The water is very clean - a bit warmer around the main town of Kos - but there is too much trash on the beach, even the more isolated ones. The beaches near the towns are narrow (restaurants, bars, cafes, etc. spread their tables on the sand), near the street (i.e., noisy) and crowded with people, sunbeds and umbrellas. You have to go quite a way to find a quiet spot.