Unwind and stay on what of the casas on the water. We stayed at casa perico which is great if you’re traveling (at least) in pairs otherwise I’d recommend finca Tati for solo travelers. 

http://www.casa-perico.com/

Go to some hot waterfalls 

I usually like looking at waterfalls but not always getting in them as the water is usually freezing. Well, if you’re like me, you’re in luck as these are boiling hot!! 30min from Rio Dulce’s city centre by bus. You’ll need to stop at Finca Paraiso. The road in front of there will lead you to the waterfalls which are a 10min walk. After you’ve bathed in some hot springs make sure to cross the roads to the fincas (approximately 20min walk from the main road) and have lunch there. You’ll find some luscious giant palm trees on the way too  

Sundog: Our host told us this place had the best pizza in Guatemala and we had our doubts. After traveling a month in the country I have to say, it’s probably the best I had there. You can order pizzas in all sizes and add any toppings you like, such as my fav' artichoke!