If you get Toyota buckets from a similar generation truck, they'll mostly bolt right in. What year is your truck?? On my '84, I installed some buckets from an 87 and the outer 2 bolt holes lined up on each side, and I just drilled the inner 2 bolt holes on each seat. The front bolts sit up on a rail that is factory installed and the holes are easily drilled. The hard part is getting a nut on the backside while the seats are in there, but with a little flexibility, you can stick your hand in there and hold the nut with an open end wrench. The back hole goes straight thru the floorboard and is easily installed as long as you've got someone to lay under the truck and hold the nut on the bottom. You'll also have to install the seatbelt buckles onto some new bolts on the floor, as you'll lose their install point when using the buckets. Be sure to install some LARGE washers (3" or so, go to a race shop to get 'em if you have to) on the backside of the seat and seatbelt bolts to keep them from pulling thru the thin sheetmetal floor in the event of an accident.
HTH,
Ryan