Down the road I will be moving to PHP. When I do, I will learn to use the SharePoint rest API. For now I'm working with pages that were created using classic ASP. At this time, I'm not going to rewrite the page and simply modify the data source from the SP 2010 SQL Server to the SP online list.
To achieve this, I created an access DB in which I linked the list. I then created a make table query that I can run before I do the import of data. This will allow me to connect from access to the SP 365 site and fetch records (calendar events) into a temporary table. I can then use this temp table as my source since it's local to the web page doing the import.
The problem I found was that I was unable to directly query the back end DB for SP 365 so I used an Access DB as an intermediary. The issue then became that the Access DB needed me to provide credentials for the site and wouldn't ask for them when I ran the query against the DB. Thus I had to create a make table query and run this programmatically upon open of the DB. This allows access to prompt me for credentials to the site and store the records locally. It's then business as usual.