What is the most complete method to download a website and get all of its files—html, images, js, css, etc.?
You could of course use DT Pro’s download manager:
Open the Options panel via the action/contextual menu of the download manager, select the desired file types and select the desired method to follow Links (“On same host” is probably the one you’re looking) for.
Finally, select the download destination in the action/contextual menu by (de-)activating “Import files to database”, add the URL of the website and start the queue.