Well, if the trailer has electric brakes, you'll need a "brake controller" in the tow vehicle. I have no idea if your vehicle already has one installed. Or if it's even wired for one. I doubt very much that it came with one from the factory. But maybe one was installed at some point since it was new.
Do you have a 7-way plug near the hitch on the back of the tow vehicle? If yes, that's a good sign. However it doesn't mean you're capable of controlling electric brakes.
Here's an example of a brake controller for your vehicle: Tekonsha Brake Controller with Wiring for Toyota 4Runner 2004 - 90885-3040P
Since this kit is available for your vehicle, I assume that it has a 7-way plug and is wired correctly to control the trailer brakes once the controller is installed.
Do you have such a device mounted to the dash in your 4runner?
Get your brakes squared away first, then you can think about the 12v+ feed at the 7-way for charging the camper battery while towing. But that's probably another thread.