Most of them fit, but I've noticed a few forts right along mayor roads, where I just can't see a reason for letting them fall apart, hell a few of those forts actually have the road going right through them. You'd think that the Empire, Stormcloacks, respective Jarls would at least care about that.
I would think yes, but than again I am from a culture that avoids uncertainties like the plague. Nords are a more wild bunch, they care little for the walls, as can be seen wen looking at Whiterun. The Empire made sure the roads and forts were maintained, just look at how they looked in Morrowind. Now that the Empire is in decline all the forts go down with them, I like this notion.
Only Oblivion was weird. The scale was too small for the capital of the Empire, but the roads were also small and the forts all inhabitat by bandits. It made little sense for the capital province. Budget and console power was most likely the reason why it wasn't bigger and why no legions marched through the land. This is why going back to a backwater place was a good idea.