I currently run 285/70-17 General Grabber A/TX on SR5 4Runner wheels on stock suspension and get minimal rubbing al full lock and with significant steering angle over bumps (such as pulling into a driveway). The rubbing is pretty slight, and hasn't bothered me enough to do anything about it. Off road I've taken the suspension to max articulation and got no rubbing in the rear either. I have tried and failed to get the this size into the stock spare location, it touched the panhard bar and the hitch. I think different years have different hitch styles that may get you more clearance. Also if you still have airbags be sure to check clearance with the suspension in low because this moves the rear axel backwards slightly. I have heard that you can get the spare in the stock location if you deflate the tire and/or compress it with a ratchet strap, but I have never tried. I just keep the spare in the trunk.
My wheels are 17x7 in with +15mm of offset. The offset is what really will affect your rubbing, and +15 mm is the sweet spot for minimal rubbing on this tire size. Generally I don't think its possible to run a 285 on the stock wheels, +25 is the stock offset, because the tire will hit the upper A arm but you could certainly do it if you also run 10 mm spacers. I do not know what the minimum offset you can run and clear the A arm is, but the more positive offset the closer to the body mount you get at full lock. As you remove offset, like 0mm, you poke the wheel out of the wheel well more and start to get really bad rubbing because the outside of the wheel has traveled a greater arc length by the time it gets to full lock. To further complicate matters not all tire manufactures make tires exactly the same size, so not all 285 are equal.
TLDR: Yes you can you can absolutely 285 on stock suspension, but you will absolutely rub. Whether or not you can live with the rubbing (or else you need to cut away plastic) depends on your offset. If you're putting these tires on stock wheels, buy 10mm spacers. If you're going to buy wheels buy 4Runenr wheels.