Jerri,
You asked a few questions Nicaragua that I believe I can answer. Being a Nicaraguan-American extremely proud of his heritage, I have visited and researched much on Nicaragua and believe that I may be of some help.
You asked whether it was "safe" to go to Nicaragua or not. Like any other country, there are some areas that you don't want to go to, but that doesn't make the country unsafe. The general American conception that Nicaraguans despise them is exaggeratingly wrong. Nicaraguans are warm and friendly people, generally speaking, and most, if not all, would greatly appreciate your visit. You also asked about cities to visit. Granada, continental America's oldest city, has a variety of attractions that please tourists, such as las isletas, a series of islands in lake Nicaragua, la casa de los tres mundos (house of the three worlds), and many other tourist attractions. Selva Negra in Matagalpa, sporting a German theme(established by Germans in the late 19th century), would be something to look at. Montelimar, on the outskirts of Managua, is the best resort in Nicaragua (very good food, I must add

). San Juan del Sur is, in my opinion, the home to some of the most incredible beaches in Central America. Nicaragua is also host to many dormant and active volcanoes, which are interesting to see. As it can be noted, Nicaragua hosts a myriad of tourist attractions (I have only named a small fraction) that would interest anyone.
Hopefully this information was of some help.
-nicaOne