My 1990 4wd, 4cyl 4Runner has over 350k km. Still runs great. Was advised the other day during an oil change that the RF inner/outer tie rods, RF idler arm, LF upper ball joint and all shocks need replacing.

I have done some reading on the internet (including this site) and have a bit of a plan, however, would appreciate some further advice.

For the tie rods I found a toyota part that seems to be the complete inner/outer tie rod assembly (45460-39505). Would it be better to purchase this entire assembly? Also, if I replace on the right side is it advisable to also replace on the left (so that both sides are updated)? Is this a fairly easy replacement - can one with basic mechanical skills/tools likely complete?

For the idler arm there is quite a range of prices. My Toyota dealer quoted me $445 for the part. It appears that I can get the genuine toyota part online (Toyotapartszone) for $200. Then I see that you can get other brand ones such as the Sankai for $128 (Partsgeek) which is evidently the company that makes the oem? I have also seen some comment that perhaps one can just replace the bushings on the original idler arm - does this make it as good as new? And with the idler arm repair are you best to do both sides? Is this a fairly easy replacement - can one with basic mechanical skills/tools likely complete?

For the upper ball joint should I stick with original toyota parts? Again, am I best to do both sides? Is this a fairly easy replacement - can one with basic mechanical skills/tools likely complete?

Any recommendations on particular shocks?

Perhaps most importantly are there any other key parts/components that I should probably be looking to replace at the same time?

Thank you for your comments/advice.

You can rebuild the idler arm, there are several how-to's if you search the web.
As for brands, I try to avoid brands I've never heard of and some of the big chain parts store bargain brands. There's a couple of tools that make separating the ball joints easier (commonly referred to as a pickle fork), HF carries them at a reasonable price.