You don't have to do the rivet-cutting method to change radius arm bushings, but some people prefer it.
The straightforward method is to just remove the radius arm itself, which involves removing the wheel/tire, spring, shock, and then unbolting the radius arm from the TTB. You usually have to yank the TTB forward a little to get enough room to pull the radius arm out of the bracket.
You'd benefit from doing it the rivet way though, since the 2" springs are causing that severe angle and a set of 2" drop brackets would do wonders. You might also find the brackets have enlarged/damaged bushing holes from driving with damaged or missing bushings, and might have to replace them anyway.
Whichever way to decide to do it, take 'em off and get new bushings. Polyurethane ones from Energy Suspension are a lot more durable than rubber.