We have a problem in my area with people gating public roads. While they may own the land on either side of the road, the road itself is still a public right of way.
I actually just had such an issue a few weeks ago exploring a local state forest. A random guy stopped my buddy and I and claimed we were trespassing. We were on a well marked and established road leading into a section of the state forest. There was even a PA FS gate, a "welcome to _____ state forest" sign, and markers indicating it was the correct fire road we were looking for. He rambled on about how it was his land, we were trespassing, how there were restrictions on the stream crossing, etc, etc, etc. We were polite, respectful, explained according to our maps and the signage it's a forest road with no private restrictions. We also explain how we had run into some PA FS workers and they said nothing to us about any restrictions, nor were any posted at the entrance to the road. Eventually he gave up and claimed he was going to talk to the PA FS workers up on the mountain.
My personally philosophy, and this may not sit well with everyone, is if the road is listed on maps as a public road then I am entitled to travel it. If there are signs posted saying "private property" and/or "no trespassing I acknowledge that applies to the land on either side of the road and will respect the signage accordingly and stay on the road. If there is an unlocked gate I will open/close it accordingly. If it's a locked gate I will usually mark the location and contact local law enforcement or ranger station to enquire to the legality of the gate and if it is legal recommend they update maps accordingly. In the event I am encountered or confronted by someone my usually response is, "According to my maps this is a public road." I always do my best to be non-confrontational and try to deescalate the situation. A lot of times once I explain who I am and what I'm doing, and that I'm just "passing through" they let me on my way. In rare instances I'll even say, "If you would like to charge me with trespassing you can call a Ranger or State Police Officer and I will wait till they get here." It's amazing how quickly people clam up and change their tune in that situation.
Anyway, long story short, it pays to do research ahead of time. Examine maps - multiple maps. If it shows up as a public road on multiple maps then it's more than likely a public right of way even if the land on either side of it is private. In such a case the land owner has no right to gate the public right away and in/around/near state forests, parks, and game lands, it is extremely illegal because those are access routes for fire fighters (I have a story about that too, but I'll save it for another time). There is also a difference between a sign that says "private property" and a sign that says "private road." There are roads that show up on maps but are signed and marked "private road." Those I always respect, but usually they are dead-end roads anyway. More often than naught i've found through roads in/around/near public land are going to still be a public right of way. I also do my best to stop in at ranger stations when traveling to ask them if there are any known such cases on a road I plan to travel. Never hurts to ask ahead of time.