There is a place in Hampstead NH called Cruiser Solutions. They mostly work on Toyota Land Cruisers. But I think they will work on a 4Runner. They are suppose to be excellent. Even if they won't work on a 4Runner I'm sure they could steer you in the right direction.
Just wanted to add to this. I just got my TRD Pro suspension installed by BDR, and they were excellent. Quality work, decent prices, great people, priced under their quote, and taking less time than expected. Free loaner cars are icing on top. Highly recommended!!!
I drove from Cambridge in rush hour traffic. Took me about 1 hour to get there and two hours back. Ugh. The city is filled with terrible mechanics. Good ones are very hard to find. Well worth it though.