I'm using your Go2wpForo tool to migrate from SimplePress. Your tool asks for 'Full path to SIMPLEPRESS attachments folder'. SimplePress has 1 folder for images and 1 folder for attachments (like pdfs). How do I migrate both?
The directories and files will be left in the same place of your server and website. So I think you should not worry about images and files. You should put the attachment folder and try it. After the migration just check both and make sure both exist in posts. You can delete Simple:Press plugin, the database tables, but you should not delete image and attachments folders. They are still in use in migrated posts by wpForo. All new images and files will be saved in wpForo folders very close to the Simple:Press image and attachments folders, because all those are in WordPress /wp-content/uploads/ directory.