Is there any way to download sites from Google Site?
Yes, you can download a complete site or just a bunch of pages with every separate file.
A windows application called HTTrack makes it possible to download whole site with all separate files.
- Download HTTrack from here.
- Open it and type the url or site domain to wich you want to copy.
- Choose the folder where you want to save it.
- And run the process, make sure you have stable internet connection.
- The process will be finish as it's total file size.
Source: Quora
While you can get a hold of some basic content using HTTrack or equivalent, you don't need to download the website in order to publish it. Google Sites will publish the site for you, (instructions) from within the Google Sites editor.
The site can even use your own domain name if you have one. The instructions assume a personal Google account, there is a slightly different process for a G-Suite for Business Account.
For unix people:
wget -e robots=off -m -k -K -E -rH -Dsites.google.com http://sites.google.com/a/domain/site/