This is one of the few detailed games there are on insurgency. Actually, there is almost too much detail; there are a lot of subsystems and moving parts in the game but with time you will get it all down.
Solo friendly, yes - there is no hidden information. Replayable, yes - there are scenarios both in the game and in the Wargamer magazine later, and there are many different ways to play the game. Difficult, not really but sometimes there is a lot to keep track of.