mm, i wouldn't block nay nodes, i'd take my fleet and go geurrilla.
have all the civilians run like hell, and sacrifice 3 or 4 systems as a frontline, and have packs of 1 destroyer, 2 corvettes, and 3 or 4 cruisers occupy large positions, and have packs of large fighters or small cruisers, Heavy Patrol Vehicles, running around.
the HPV's would have a crew of 5, food, water and missiles for up to 2 weeks, and be equiped with 3 turrets on the sides and back, and heavy fighter weapons up front. like 3*4 primarys, with the abilty to mount different ones with 5 minutes work, and 4*lots secondarys, with the same thing like the primarys.
they'd be resupplied by support ships send from cruisers or small asteroid bases, and have intersystem drives.
they'd hunt in packs of 3 or 4, and attack anything from fighters to corvettes, or destroyers when they've got bomber support from the destroyers. the commanding officer would be ranked a commander, but the leader of a pack would be a captain.