Second this^^^
If you want it for cargo, go Tacoma.
If you want already built-in secure space for your gear and passengers, be able to stop anywhere you have to (i.e., to camp in bad weather), and just crawl into the back to sleep/camp/access gear instead of having to get out of the cabin, walk around the back to the camper/truck cap, etc. Go MoreFunner.
Also consider the length of vehicle - for tight places when off-roading; I think Tacoma is generally longer than the 4Runner.
This I'm not sure about:
Is the 4Runner, just as "flat-bellied" as the Tacoma? FB meaning nothing sticks out from below the chassis line - safer, better ground clearance and easier to install armor.