I just purchased a cpo 2017 gx460 premium yesterday. I have not looked at a 4Runner since my 89, which was a great truck.
the cpo has an unlimited mileage bumper-bumper warranty to 2023 and can be extended to 2028.
Nobody wants to negotiate until the end of the month, quarter, etc. I saw a lot of positive comments etc. about the gx460 but some criticisms too — older interior design and styling, etc., the rear door, etc. I don’t care. Mine has low mileage (16k). I tend to put a lot of mileage on vehicles so the warranty was a big positive. My son has a 2009 lx470 with 175k miles on it.
I did do a lot of price comparisons between dealers, etc. online and the usual sites for feedback, etc. The gx460 seems to have a good resale value.
I assume much of the above would apply to the 4Runner too.