Ok, it looks like the floor was sprayed with some type of undercoating and you can see over spray on the tie rod. I really hope that the underside was rust free when it was sprayed and that it isn't covering up rust. The frame rails appear to have some surface rust at least and in the last picture it looks like the floor was been repaired at one time but I can't comment on the quality of the job.
Until you look at it and get into tearing it apart, you really can't tell from these pictures. Some of the surface rust may go way deeper...