So, the fuel filter situation on the '05 4Runner is absurd. Some of the threads I read here discussed the issue, but didn't lead me to conclude it was totally unserviceable. Which it is. Here's the deal, and the solution:

The fuel filter is located inside the fuel tank, inside a tank assembly that includes the fuel pump. You have to drop the fuel tank to access it, but first pull up the carpet under the rear seats to access a secret doorway, which only is only big enough to allow you to unplug the tank assembly from the electrical systems, but not remove the assembly.

Once you drop the tank, you have to remove and completely disassemble the fuel pump assembly--including removing wires from the fuel pump connector to pass the wires through a hole in the filter. Up until this point, you think it's just an overly complicated system to get at the filter, but it seems serviceable--because, after all, you can buy the replacement filters online, and even from the dealership.

The problem is, the submersible plastic hose that connects the filter to the fuel line is not serviceable. It is molded to the nipple that connects to the fuel line, probably by heat during manufacturing. You can get the hose with some of the filters, but the diameter is too small to pass over the nipple. I tried heating it with hot water, then boiling water, and it never became pliable enough to get it over the nipple. I took it down to my local old-school auto-parts/machine shop store, and the guy just shook his head. He called up a buddy who works at the local Toyota dealership who went off on a rant about those things. They're considered by Toyota to be not serviceable. You have to replace the whole tank unit, for about $600. They claim it's not necessary to service, but that seems patently absurd--and in fact, Gadget at URD claims they've done tests showing these filters can lead to fuel starvation and too-lean air/fuel mix at only 30K miles.

I went home and made one more effort to fit the hose, this time by heating with a heat gun, and it deformed the plastic hose. No way to get that thing on and have it withstand 100+ psi.

Gadget rescued me with a rush shipment of a replacement fuel pump with an external filter. He recommended the Deatchswerks 255 psi pump for my application. The pump will arrive tomorrow, and I should be back on track.