For Tikal, Yaxha and other hikes check out: http://www.cafeyaxha.com/go/tours.html I believe October can be very wet though so expect mud.
Volcanoes... my number one would have to be Acatenango from Antigua. It is a very hard steep hike up (make sure you are acclimatized) but you go from farmland to cloud forest to high alpine forest to volcanic scree. Looking down on the clouds, seeing volcano Agua and then on top seeing volcano Fuego erupt is amazing. We saw lava at night. The sunset and sunrise were spectacular. We went with OX. I recommend the overnight trip.
Number 2 for me is Santa Maria from Xela. Also a hard climb. Again, you will look down on a cloud blanket and as you go higher the views of Xela are amazing. At the top you can see lots of other volcanoes and of course you look down on active volcano Santiaguito. Seeing Santiaguito erupt is spectacular. Moreover there are almost always Maya people at the top chanting and praying. If you climb up on a Sunday you will climb with lots of Maya families. Again, it is the rainy season and clouds do roll in quickly so you have to leave as early as possible. If you get to the top and there are clouds you might still have a view of Xela but you wouldn't be able to see Santiaguito which is lower. We went with Kaqchikel Tours.
Number 3: Tajumulco, also from Xela. I recommend the overnight trip as the sunrise is amazing. This climb is less hard than Acatenango and Santa Maria.
Here is my trip report of our climbs:
Santa Maria : 3, 772 m height. 1300 m elevation gain in 11 km.
Tajumulco : 4,220 m height. 1200 m elevation gain in 13 km.
Acatenango : 3,976 m. 1700 m elevation gain in 6,5 km.
Santa Maria : it took us an hour to reach the mesa and we could see Santa Maria in front of us, bathed in the light of the morning sun. It would take us another 2 hours to the top. Apparently 3 hours is great… average time is 4 hours. It was steep but our guide had a slow and steady pace that suited us well. I loved staring at the white cloud blanket beneath us. When we were almost at the top we heard a boom… Santiaguito erupting. That is the best part of climbing Santa Maria : the views are incredible but as an extra bonus you look down on Santiaguito and that volcano has been very active lately. The boom made us walk a bit faster… summit fever ! At the summit we didn’t get any rest as our guide suggested hurrying to the other side so we could see Santiaguito. It was such an impressive sight. Santiaguito was emitting smoke and from time to time we saw venting from the sides and steam and rocks rolling down. We also saw all the volcanoes at lake Atitlan and Antigua. We sat there for an hour just being amazed when all of a sudden Santiaguito had a major eruption, a big boom and a dark mushroom cloud of smoke coming from the top… we were ecstatic. We then walked to the other side, Maya people were chanting and praying and we enjoyed the view of Xela and of the other volcanoes. To top it all off we saw Fuego (near Antigua) erupt, a small puff of smoke on the horizon. It was a great hike, we enjoyed the flowers and saw a blue-green lizard.
Tajumulco : we met our guide at 6 am and took two buses, the first one to San Marcos where we had breakfast and then on to Tuichan. We were a bit anxious as this time we would be carrying our backpacks up with water, sleeping bags and pads as we would be camping just below the summit. The trail was steep but although Tajumulco is higher than Santa Maria it is actually an easier hike up. The views were amazing, again we were above the clouds. We could see Tajumulco and volcano Tacana on the border with Mexico. We reached our campsite at 4000 meters in just over 3 hours. We set up camp and had lunch. The next morning we would climb the last 220 meters to the summit to see the sunrise. Tajumulco is the highest peak in Central America (4220 meters). We got up early and climbed the last 220 meters to the top in the dark. It was hard and I struggled a bit. But we still made it up in 25 minutes. The sky was starting to light up, the clouds beneath us were amazing, the volcanoes in the distance spectacular especially when we saw Santiaguito and Fuego erupt in the distance. The sun came up and we saw Tajumulco’s shadow projected on volcano Tacana. We then took a hike around the crater, so impressive and the light kept changing, the colours, the clouds, the views of the plains into Mexico. We made it down in 1 hour and 45 minutes, just in time to catch the bus back to Xela. The bus ride back was very crowded (8 people in a row !).
Acatenango : so Saturday morning we made our way to the office of O.X. We got some more things to add to our backpacks (food…) and we drove to La Soledad. The guide handed us a stick and off we went, a steep climb through farmland. There were lots of clouds and when we entered the cloud forest clouds were all around us. After the cloud forest we came to the alpine forest and then reached the old crater. By then the sun had appeared and our guide said we would be able to climb to the summit and camp there. We had wonderful views of the clouds beneath us and great views of volcano Agua. The last part was hard… very steep and the volcanic scree made it hard to go up, we kept sliding down. But when we reached the top we did not even head down into the crater where we would camp, but went along the ridge to get a view of active volcano Fuego. We had a clear view of Fuego. Then an eruption and a cloud of smoke ! Later a bigger eruption with a black mushroom cloud and rocks (boulders probably) and debris flying in the air. It was magical. The view of Agua was wonderful too. Plus other volcanoes poking out of the clouds. We watched the sunset, the colours were unbelievable. After dinner we were all very cold. It was very windy. We retreated to our tent but it was hard to get warm. At 2:30 am Ray could not stand it any more and we got up. We climbed to the ridge. The wind was howling. We sought protection between some rocks. We saw the top of Fuego appear out of the clouds. At 2:50 am Fuego erupted, we saw lava shoot up in the air ! Twenty minutes later another eruption, sparkling fire with lava flowing down the sides. We wanted to just stay there but were freezing so went back to the tent till about 5 am when we got up again for the sunrise. We saw the Pacific, Agua, Fuego of course and Lake Atitlan with all the volcanoes around it. Add to that a full moon. It was really breathtaking.
Going down was much easier and fun. The volcanic sand is hard to climb in but going down you can actually run taking large strides.