Really late to the party here, but I just wrote a google script that might be helpful. It takes an html table file and converts it to csv.
I'm replacing all the table tags with commas where necessary or removing them altogether. You may have to massage it a bit for your specific use, but it's working for me.
There's probably a more elegant way to do this... but here you go!
var blob = DriveApp.getFileById(id).getBlob();
var string = blob.getDataAsString();
var newString = string.replace(/\r?\n|\r/g,"").replace(/<\/td>/g,",").replace(/<td[^<>]*>/g,"").replace(/<tr[^<>]*>/g,"").replace(/<\/tr>/g,'\n').replace(/<br>/g," ").replace(/ /g,"");
Logger.log(newString);
var csv = Utilities.parseCsv(newString);