How can I remove carpet adhesive from hardwood floors?
Re-did some floors a couple of years ago with the same situation, two layers of carpets on hardwood floor with the bottom layer glued down. We used heat gun and scrapers to remove most of it, and then some glue remover on the worst parts. After doing this the person that came in and re-did our floors said that was not needed, especially the glue remover. He said the sander  would have taken it all off.

So I would still probably try scraping up as much as possible and then let the sander do the rest of the work.