Road block; Burned out (possibly burning to cause damage), immovable car. Would block vehicle access across a road (like Sandbags) and cause mild infantry damage (Razorwire), but would require some form of building and maybe a molotov to set it burning (but it doesn't stop burning once started). Same way to get rid of it as anything else; big gun shooting it enough destroys it in a similar way to the burned out hull of a destroyed vehicle.
Foxhole; Not sure how realistic it would be, but a spawn point for troops. No kit request but low profile; no sound and appearing to be underground, low visuals. Destroyed by single grenade. Very limited number per round, not just at once; a limit of how many can be deployed in the whole round so once they're gone they're gone. Must be deployed >100m from a CP. Built with shovel.
Cache; Spawn point (similar GFX to current Insurgent RP) for a single RPG & PKM (possibly Mosin Nagant), provides ammo. Again, limited number per round and must be 'repaired' before weapons spawn. >100m from a CP.
All those could be setup by a Militia with little in the way of preparation, and would be in line with guerrilla warfare tactics.
[EDIT] Sorry, title should be Militia, not Insurgent; forgot which was which





