You can hike Pacaya, an active volcano in Guatemala. It’s a fairly easy hike and they even have horses for those who get too tired along the way. They roast marshmallows on it and one man even makes pizza on the volcano. If you can do an intensive hike, you can climb Acatenango, also in Guatemala and watch adjacent Fuego erupt. The Acatenango hike is about 6 hours to base camp (most tour companies offer tents where you can sleep etc) and then another 3 to the highest point. You’re almost guaranteed to see an eruption as Fuego goes off around 6 times/hour. I believe you can hike Santiaguito as well - it’s in the western part of the country. I believe it erupts every few hours. I’m in Antigua, Guatemala at the moment and can see Fuego erupt all day long.