My first trip through Guatemala was a solo adventure in 2010 on a bus.
I was traveling to the central American countries that I had not been to and met an ex-patriot doctor who lived there for 17 years. We met on the bus into Guatemala City at night and he and his wife and daughter invited me to stay overnight with them at their sons' place in the capitol.
After spending 3 nights there, I was invited to see how the real Guatemalans live in the country where they were from. I spent nearly 3 weeks in Tejutla, Guatemala and enjoyed it immensely.
The weather was very cool up in the mountains and quite hot down near the Mexican border by Tapachula, Mexico. The food was magnificent and very inexpensive. I would recommend taking bug spray.
My second trip down was driving solo throughout Mexico and into Guatemala. That car is still there. I flew back one-way. Go see that beautiful country and those very friendly people.