I've got several heaters that I'll be adding to "winterize" our 4Runners when I ge a chance, probably next weekend. I've got the block heaters for both and will be adding heating pads to the oil pans and batteries as well. I'll try to take pictures and do a quick writeup if I have time.
This setup (block, battery, oil pan) worked well on my other vehicles when I lived in Fairbanks, AK where it would regularly get down to -40°F/C in the winter. I wanted to add heating pads to the transmission pans of the 4runners too, but after crawling down there and looking at it, the pan has ridges that might prevent a good bond with the pad.
I bought Kat's brand heating pads from Amazon, they were 1/3 the cost of the Proheat or Wolverine branded ones and work just the same.