Emily Chow, Ted Mellnik, and Karen Yourish for The Washington Post mapped where the candidates and their wives have visited since June in an interactive with filters and multiple views.
On load, you see the visits of the eight, with a comparison between Democrats and Republicans. The map on top shows where, and the time series on the bottom shown when. Click on the map, and it zooms to show visits at city-level, and a click on a time slice updates a list of individual visits. Furthermore, you can select the individuals or categories for just the last 30 days, fundraisers, or your state.
The interaction lets you narrow down quickly and easily to what you care about. The only other thing I would've liked to see is a tighter coupling between the time series and the map.