Amazon Redshift has a direct connect with Tableau. When you start Tableau, please use the Connect to Data option and then choose Amazon Redshift on the left. You'll see the following log-in screen. You shouldn't need to worry about drivers. Also, the Tableau trial version is the full version, so there is no limiting of features.
You can read more here, and watch a video. Also technical details are here. You may want to try version 8.1, which is the most recent version (also has 64 bit)