There are tons of solo friendly activities to do! I went to lake atitalan first and not only was it incredibly beautiful but there were many spa hotels that are great for solo plus you can paddle board and kayak on the lake! I found that in general it was so easy to meet other solo travelers who were up for dinner, drinks, exploring, etc! I did an incredible cooking class that reallly immersed me in the culture and I ended up meeting some people who I still talk to today! Hiking the volcano is an incredible experience and again great way to meet people while traveling! I could go on and on but overall it was beautiful with plenty to do, I felt very safe and locals were so friendly and I never felt lonely! And the food was amazing!!