Dropping the sub-frame in addition to the four sub-frame bushing mounting points would require the removal of at least the rearmost section of the exhaust, it would also require the disconnection of the driveshaft, the rear sway bar and the electrical connection to the differential ABS sensor, the parking brake operating cables and the unbolting and hanging of the rear calipers(with the sub-frame out there isn't much to hang them from). A decent rolling floor jack is needed unless one is jacking the entire rear of the car high enough to leave the wheels in place and to allow the entire sub-frame to be rolled out from underneath the car.

One method to effect the disconnection of that end of the link might be to get hold of a pneumatic or electric "body panel saw" available from Harbor Freight. It's a sort of mini sawzall with a shorter stroke but higher speed, its blades are about 4 inches long and pretty thin. You could cut through the bolt by placing the cut between the link's bushing end and the chassis mounting point. If you're careful you should be able to cut through the bolt and avoid cutting the mounting point. Might take a $8 pack of blades but you'd be past the obstacle you're stuck at now. In a worse case situation where the bushing has corroded and "fused" to the bolt you could cut of both the head and the nut sides of the mounting bolt.

Electric Body Saw