I do feel comfortable with the repairs. I'm not inclined to tear apart the engine or anything but if the engine runs, doesn't smoke and makes no odd noises, I feel confident that I can do anything else to the mower with all the diagrams and parts available online. It's unlikely but even if I have to sink $200 into it (the battery will be expensive but I have a spare car battery I will try to use) that is worth it to me.
I do have 2 other projects that I put too much money into, lessons learned there. When I do work, I do try to think of resale just in case, you never know. So, I think that as long as I don't get say, $300 into it, I shouldn't have too huge of losses, as long as it fully works, if I try to resell it.
The guy that's selling is going to let me know what part in the steering mechanism he thinks needs to be replaced and I'll look it up & factor that into the cost.