Actually, no you don't need a spring compressor. What you need to do is loosen the lug nuts, raise the vehicle and support it with jack stands right behind the radius arm mounts on the frame rails. Then, remove the wheel and tire, next place your jack underneath the axle beam where it will allow you to control the movement of the axle assembly. Then with the axle beam supported remove the upper nut, washer and bushing from the shock. Now with a breaker bar or sturdy ratchet, a long extension and a 1 and 1/8" socket( deep well maybe necessary) remove the nut that is inside the coil spring at the bottom. You may want to spray some penetrating fluid on this a while before you attempt to remove it as the nut can be very rusty. Ounce the nut is removed fish out the large washer that holds the spring in place and you can slowly lower the jack as you do the spring will loose tension ounce the jack is down you can begin removing the spring usually the spring can be removed simply by rotating it and it will sort of twist off the retaining tabs at the to of the spring tower if not simply use a suitable punch to tap the retaining tabs inward and remove the spring. Assembly is the reverse just be sure to have everything tight and the tabs at the top bent back around the top coil of the spring. Hope this helps.
Need a spring compressor, if u do not have access to one, take to a shop. as u can get hurt w/o one.