Hello! My sister (21) will be traveling to Guatemala for two weeks in January 2016 and I am trying to help her figure out safe travel around the country (also bc my mom is worried as hell). I lived in Ecuador for a while two years ago so I have general travel knowledge for South America, but hoping to get more Guatemala-specific responses. My sister is not fluent in Spanish, though she does have some understanding of the language, and this is her first international trip- just FYI. Thanks!

Her flight arrives in Guatemala City at midnight. Any ideas for lodging and travel around the city that late at night? Anything to look out for? (my thoughts: private taxi? hotel shuttle? dont leave the airport? hah)

The following day or so she will be traveling to Lake Atitlan. Again, any specific travel modes/companies you would suggest? To avoid a long list of questions, any other advice for my sister would be greatly appreciated, by myself and my mother. Thanks, Reddit!