I'm not saying that they get a free extra road.The smaller roads (not on the map) count as off-road for a reason. Those that have ”navigated” backroads before the era of gps remember how easy it was to get lost, especislly without maps.
Add to this the changes that war makes to roads and yeah, it will not be as easy as following 4-8 lane partly ruined highway.
Winding backroads with twists and turns and craters and not clear roadsigns might be easy to follow on google earth but not so easy while driving there without a map.
I really like the FL approach here: all hexes have roads but the only the main ones that are easy to follow are marked.
I'm just saying that to the players, it looks like they're just trekking through wild woods, when in fact there's roads going in specific directions there.
I'm using it as a tool to let my players know that there are (or, were) roads going in X direction that they can nominally follow. Sure, there will be obstacles that mean they have to leave the road occasionally, and the risk of an ambush is much greater, but it does mean that they get to follow something in the right direction.
When they decided to go towards Örebro on one of those roads, it still counted as going off-road due to them having to go around obstacles every so often, and it did mean that they ran into a marauder roadblock while driving.
But, it also meant that they didn't have to roll to make sure they were going in the right direction. Since they were following the roads general direction.