Doing some work to my buddy's 2002 4Runner, that has one ton axle swap. Currently, it has the stock ABS module, without vacuum booster, I assume it's electric (it's been a few years since I sold my 4runner, so I'm out of the loop). Braking is decent, but would like to replace the whole thing with 1 ton master. Has anyone done this?

Correct that it's electric. That's all the help I can give you since I've not been underhood on once of those enough to know a work around.

I swapped mine from that style to the vacuum style- it bolts up no problem.
You have options for his setup.
I also just swapped a 3rd gen 4R booster into my buddy's '85 on tons. It's a GREAT booster to use with Chevy masters, cause you don't need to use an adapter like you do to use a Chevy master on the 4-bolt Toyota boosters. You still need a push rod adapter, but no adapter plate. There are newer Chevy masters that are better than the old 400lb unit- like from an Escalade, newer Camaro, Eldorado, etc. I have all this info, so if you go this route, I'm willing to help you out with it more.
The other option is to stay Toyota. You can swap in a large dual diaphragm 1-ton T100 booster and master. The T100 1-ton master is a 1-1/16" bore, which is the biggest Toyota master I know of.

If you go vacuum style, the T100 stuff is mostly a direct bolt in. Just did it in fact. Just have to rebend the lines.