How much research is too much?
I'm presently writing about a car chase across Bodmin Moor in Cornwall. I have two old Ordnance Survey* maps, 1/2" to the mile, of the area. They're really useful to show the roads the way they used to be, before they were straightened and widened. They also show the contours, so I can tell whether a road goes uphill--in general terms--or downhill. One has contour lines at 50 foot intervals. The other is tinted from blue (sea) through greens to various shades of brown, making it more intuitive but less precise. They show every tiny hamlet, with its name, and even many farms.
And I have Google and Bing maps and bird's eye/satellite views, and in some places (but by no means everywhere) "street view." These maps tend to ignore narrow lanes, while the satellite pics don't show them when they run beneath trees. They don't show tiny places.
So both types have their uses. The question is, do I really need all that information? I've heard from a few readers who get out a map and follow the tracks of my characters, but for most people a few evocative village names and a few words of description of the scenery and the state of the road are sufficient.
Nonetheless, I find myself obsessively checking whether there's a crossroads between villages A and B, and whether the chasing car at point A would have a view of the quarry when it reaches point B. Too Much Information available!