I quite like the approach of the new asp.net (asp.net 5\\core 1.0) web apps with the wwwroot folder being the root and only static files in there being served up.
If you would like to use IIS for this you can create a rewrite rule:
You can also add a prefix to the url regex, such as ^(wwwroot|api)/.*, if this is a web-api that you would like to host at /api.
^(wwwroot|api)/.*