Hey there, I also ran into lots of trouble with the BaseURL when I started with Hugo a few months ago.
What worked for me was to set baseURL = “/” in config.toml. For some reason any other URL I would put there would fail to build the site correctly. However, you need to go into every reference for the BaseURL in the Layouts so that links don’t add another slash after calling {{Site.BaseURL}}
example that works: <link rel="stylesheet" href="{{.Site.BaseURL}}css/bundle.css">
this doesn’t: <link rel="stylesheet" href="{{.Site.BaseURL}}/css/bundle.css">
Also works: <script src="{{.Site.BaseURL}}js/jquery-2.x.min.js"></script>
Not works: <script src="{{.Site.BaseURL}}/js/jquery-2.x.min.js"></script>
You can delete every slash by running a find and replace in your editor like so
Find: BaseURL}}/
Replace: BaseURL}}
If you hit replace all, you can change all instances per page in one click. You should run that find/replace on each page in your layouts folder to make sure.
Hope this helps! Don’t give up on Hugo, I struggled a lot to understand it, but I found it all makes sense in the end after some pain and taking time to let it sink in.