GGplot2 is good, but leaflet is better at mapping these days. If you want a dynamic map, Leaflet for R is where to look. https://rstudio.github.io/leaflet/
GGplot is significantly more flexible. Leaflet is good for quick results that do not need to strictly adhere to cartography standards. Furthermore, it handles custom projections pretty poorly.
I've been meaning to use leaflet more for iterative portions of data exploration and designing a map, the stuff that a GUI and fast refresh times can speed up by an order of magnitude