Email thank you notes are not worthwhile, I think. Anybody can do that in 10 seconds.
Again, anyone can write a generic good-manners email or card in 10 seconds.
Dear X,
I enjoyed my visit to your school. Everyone was lovely and I can see myself working there.
If I can answer any further questions, please do not hesitate to contact me.
Best,
Polly MerYes, delete, delete, delete those.
On the other hand,
Dear Marge,
Thanks for having lunch with me on Thursday. I learned so much about the town that I can't get from the website. I've been thinking about your question on how to modify that lab on eggs and a possibility is to put some of the rubber bands in the freezer, some on a window ledge, and some in a drawer for the two weeks prior to the lab. That will give students a range of materials with which to work, even though ostensibly the materials are the same. That's a real-life collection of data and will make later-in-the-week labs unable to merely copy what the earlier labs did.
I had a great time and I hope that whatever happens with the search that I'll see you at the next <Big Conference>.
Cheers,
Polly