I drove a semi truck for a while and was up for a 34hr reset. I was in PA at the time, on the south end. I knew I was coming in to the period where I needed my 34hr reset so I route planned a bit to stop somewhere I could day tour on my time off. I found a gas station along a small state route that wasn't too far off the interstate I was on that had a lot big enough that I could park in (gravel). The down side to stopping there was there weren't much in the way of facilities.
That full day off I got on the bike and went off exploring. I mapped out a route and proceeded along it. The whole time I was starting that escapade I was climbing in elevation. The higher I got the smaller the road got. Then it turned in to what almost looked like a driveway with, in the distance, way over-grown trees and brush hiding the road. Something didn't look right so I turned around. Back down the hill was a teenager washing his car. I stopped and asked about the route. Apparently there are two neighbors up there that don't get along. Both on either end of that supposed "road". What ever their disagreement was, it soured things enough between them that they closed off access so each had to come in from different directions. Mind you, this is rural PA. There was a whole lot of nothing in them thar hills. However they pulled off being able to close down the road, it wasn't passable. I at least got a good story out of it and got to meet one of the locals that I otherwise wouldn't have met.
I went on another route and made it to a stream. Then after being out moping around for about 5 hours on my adventure I made it back. There was a town the other direction about 4-5 miles that had a pizza place. So I jumped back on the bike and made my way down there for dinner.
The "google maps isn't your friend" experience was the bitter neighbor road.
The "google maps is your friend" experience the same day was being able to find a bike-able route to town for dinner. The down side to that route, though, was I had to ride the state highway with high-speed traffic in order to get to the turn lane to the road that took me to town, maybe 1/2 mile of the busy road including the turn lane.
Always check the satellite imagery.
There are also a lot of cases around the country where roads that used to be there aren't there anymore. And the reverse - roads that are there now that aren't on GPS and don't show up in satellite imagery yet.
There is a portion of a trail here in Ohio (north from Xenia, way north - the last couple miles of that trail) where, last time I looked, the trail on the satellite imagery showed single track gravel/hard packed dirt with grass. When walking that portion of trail it was very nicely paved with chip-and-seal the normal MUP path width. Quite the upgrade, and a welcome one.