CSS
Moving the CSS is simple. Create new CSS files in umbraco, and paste your existing content. This went fairly smooth, except that my CSS includes URL's like this:
.container{
border-left:1px solid #C0C0C0;
border-right:1px solid #C0C0C0;
border-bottom:1px solid #C0C0C0;
width:950px;
margin:0 auto 1em;
background:url(~/styles//footer-decoration.jpg) #FFFFFF no-repeat bottom right;
}
This relative path was needed on my original site to ensure the CSS includes would work for sub-folders. However, in umbraco I found that I needed to copy the files a folder below the /css folder, and change the path to:
background:url(kadonk/footer-decoration.jpg) #FFFFFF no-repeat bottom right;
The CSS URL's are relative to the location of the css documents. Perhaps there is a better solution, if so I will update this post later.
Scripts
In order to be compliant with the idiosyncrasies of Internet Explorer, my old site is relying on the fantastic IE7 JavaScript Library which resolves the incompatibility of IE with I suppose every standard ever made.
The IE7 library was easy to copy, I simply dropped it in the script directory directly on the server, and reloaded in umbraco. Pop, there is was. Beautiful !
MasterPages
Converting master pages is really an exercise in putting back together what was once apart. On our old site, I have about 20 nested master pages. Perhaps not the best way to construct a site, but that was what it evolved too. With umbraco, these can go away. My main reason for the master pages was to contain sub-menus, but with the document templates, this seems to be a much better and easier way to do so. Especially since umbraco can generate the menu's more or less automagically.
Editing the templates however provides the first great shock of umbraco: What a crappy crappy editor. I miss Visual Studio's highlighting, intellisense, and just automatic indenting. Instead I go back to the stone age with a messy basic text editor. Woe anyone making a mistake in this editor, there is no help to be had. Indenting is manual, like back in the 80'ies. I cry a silent tear, but press on...