Well, getting 90% of the tiles off was easy. It was the last 10% that took a lot of elbow grease. I don't know what kind of floor adhesive Airstream used 40 years ago, but it sure is strong! At first I started with a chisel and a scraper. Then I found a large heavy tile scraper (silver tool). Sure was worth the $20. I had the scraper sharpened on a grinder and it worked great!
You can see the various stages of cleaning the floor after all the tiles were pulled up. The mastic (tile adhesive) is black and nasty. If you try and sand the mastic the sand paper will get clogged up with the gluey stuff. So I used JASCO adhesive remover then scraped the mastic off. After the plywood was scraped, I ran a belt sander over the floor and it looked like new!