Hi Chad.

Do we talk about template itself or whole website? Yes, a huge difference!

Helix Ultimate is Joomla Template, like Casiopea template. And only website contains text, images, modules, users, comments, etc.

Each template has (or may have) different module positions. But in general, anytime you can install a new template and set it as default only for selected submenu items, to test & preview what more you have to do to make perfect design. It means that you can make changes without worring that something may be broken for viewers. If older template is also based on Helix Ultimate, switching from template A to B, is very easy process. In other cases it will time more time & efford.

Just now getting back to this... If I could ask for a bit more clarification...

I understand that the site I would be moving the template to would need the modules created and images moved, etc. but for the template itself is there a way to copy over all the layout, custom css, etc. (everything that you see when you go into Template Options)?

Or is it where I will have to just install the base template then copy/paste everything over, modify the layout, etc.

In theory yes. If both templates are based on Helix Ultimate - there is possibility to Export & Import template settings, read more in Helix documenation. After all you can have the same settings (layout, logo, custom css) on second site. Of course all files like custom.css or logo files you have to transfer manually. Then you have to set all modules etc. About content (articles, menu) this is a different story.