So, a new idler arm, but what else?

I would have to agree, If that one part is worn others may be as well. I would go over the front and rear suspension with a fine tooth comb. Once you have a list of what needs attention. Prioritize in two ways, first safety and then second into a order that you are not doing the same task multiple time. For example you have a bad lower control arm bushing and so so strut rods bushing. It would make more sense to do both at the same time sense that portion of the front end is apart. Also think about your budget???? What kind of car do you want to build..... Cruiser, Pro-touring, or drag and pick the best combination of the parts and put them into and order as well so that you are not doing redundant tasks.

Thanks
James