About 10 hours for me. I'm a pretty good for a hack, but had trouble with threads stripping on the fan mount I believe. I prefer to go slowly and clean and inspect everything I can get my hands onto. So I am kind of slow.
It is not too hard if you have reasonable skills. Read the threads on the forum for others experiences. I also posted pictures you can browse.
land_cruiser_timing_belt Photo Gallery
Some folks have had it done for impressive prices (<$400 labor) I would be very tempted at those prices if you have someone you trust.
Good luck,
Pete