You should be able to use the available property to build the url you require. Just be aware that many of the property must be accessed with a *get_method* sintax.

For the SP.Site use [the get_url() "property"](http://msdn.microsoft.com/en-us/library/ee550732.aspx).
For the SP.Web use [the get_serverRelativeUrl() property](http://msdn.microsoft.com/en-us/library/ee550064.aspx) and build up the full url.

For the list... don't know if there is an easier way, but you can resort to the [get_serverRelativeUrl()](http://msdn.microsoft.com/en-us/library/ee547617.aspx) property of the root folder ([SP.List.get_rootFolder();](http://msdn.microsoft.com/en-us/library/ee551348.aspx)). Then build the full url from there.