Located in the Western Highlands of Guatemala and about a 2 hour bus ride from Antigua, Lake Atitlan is a beautiful volcanic lake ringed by dozen of small towns. Panajachel is popular with travelers and a good entry point, while San Pedro La Laguna (has a reputation as a major backpacker hub) or the "less party, more meditation" village of San Marcos are off-the-beaten track. Lake Atitlan is a combination of scenic beauty, a relaxed atmosphere, easily accessible Mayan culture, and a good tourist infrastructure.
Women digital nomads should dress conservatively and avoid wandering around alone after dark. You will most likely experience cat-calls while walking down the street, just look straight and don't acknowledge. There are towns that are safer than others - for example, Panajachel and San Marcos might be safer. Take a tuk-tuk or walk with a male friend after dark. During the day, it is generally safe to wander around as a woman alone, just don't go wandering down sketchy alleys. If you are traveling between towns (i.e between Panajachel to San Marcos), it is safest to go via boat, or lancha. Even the locals avoid driving on the roads connecting the towns due to armed robberies (especially the road between San Pedro and San Marcos) and landslides during the rainy season.
Lake Atitlan is a popular destination for digital nomads, some who plan on staying for a couple of days but end up staying for months. Wifi are very likely to be slow or at best decent (most hotels, restaurants and house rentals offer 2MB to 5MB download speeds), and connections may not be reliable. Note that power cuts can be a problem during the rainy season. Skype calls are generally poor, and cell phone speeds varies greatly depending on your location - Tigo has the best cell coverage across the lake.
The dry and peak season is from November to April, and mornings and nights are cooler - you'll need a sweater and long trousers. The wet season is from May to October, when it rains mostly in the afternoons and evenings.