The hardest part is getting the a-arm out. I think it is debatable whether you need to ream in new bushings. If the bushings are not visibly scared, leave them be. A racer friend of mine claims that he has replaced hundreds of a-arms and never replaced a bushing. Eric Jones of Riverside motors sells rebuilt a-arms with new fulcrum pins and king pins assembled as a unit. Makes replacement much easier, and his prices are very fair. PM and a I will send you his number.
Stay far away from the king pin kit VB sells. The upper fulcrum shims that came with mine where too big and caused the king pin to bind. PeterC sells shims that work great and cost about 35¢ a piece if I remember.