I've got 235- 80- R16 tires on my truck right now that are in pretty rough shape. I've been offered a set of used, but in better shape, 225-70-R16 tires. Will these fit until I can spring for some new tires of the correct size? Thanks.

That's a pretty drastic downsize from what you have now both in profile and size. You'll be using up more gas, and spedometer calibration will be off.
I would keep looking.

Ok. I'll pass on these, then. Thanks a bunch!