If I have a P0705 code on an '07 Toyota Land Cruiser, then is it ok to drive it?

That's a hard question to answer. This indicates a possible issue with the Neutral Safety switch and/or wiring. In my experience with TLC's usually this is a bad switch and will not cause a problem driving, at least for a little while. However, it could cause the trans to go into a false neutral. I would bring it in for service ASAP to be sure.