Here is a great article by Art Kramer why people are traveling to Central America and some are even considering investing in real estate.
The writer states "Mombacho Volcano Nature Reserve where you can reach the peak (1,400 meters above sea level) on foot or by vehicle." To reach Mombacho you better have some stamina to hike up, take at least 1.5 hours, and if you travel by car the vehicle must be a 4x4 vehicle, otherwise excess will not be granted.
If you come to Granada area I strongly recommend you stay at Hotel La Merced and take time to visit one of the active volcanoes nearby. Enjoy your travel and exploration of this beautiful country called Nicaragua.