I don't agree with the above assessments about there being 'plenty of parts'. It is the case that there are several parts suppliers out there. It is the case that there are some aftermarket parts available. It is the case that Toyota will have most of the parts to keep a rig running, like bearing, seals, u-joints, gaskets and the like.
But if you are looking to restore a rig, you will find, after a while, that there are a lot of OEM parts which are NLA (no longer available) from Toyota or anywhere else. Parts like body panels - only the hood is still available as far as I know, and those are on a short list now. Interior parts, like steering wheel, heater, console dash pads, instrument clusters, cable controls, headliner, seats, door panels, door limiters, floor mats - forget it. The best chance you are generally going to have are those Toyota parts which were shared across several vehicles. As an example, I obtained sway bar bushings from my local Toyota dealer last week, and those bushings were in three different Toyota models besides Landcruiser. Need new pistons for your 2F? NLA. Need glow plugs for your 2H? NLA. Need a glow plug relay for your BJ42? NLA. I find the answer to my question at the Toyota dealer is 'NLA' or 'de-listed', or 'obsolete' about 90% of the time. Then sometimes they will have a part you didn't expect them to have and it is like a surprise Christmas present.
In some cases there are good aftermarket options for some parts - Joint Fuji tie rod ends, u-joints, and parking brake drums, for example, which are OEM quality. Other aftermarket parts can be cheesy, like Taiwanese indicator lamps.
Once you get really familiar with these vehicles, you can get kind of like 'mammoth hunter' in your mentality when a rare OEM, NLA part shows up on Ebay. The last time I saw a late model steering wheel come up on auction, it went for over $400.
YMMV. good luck!