You could try my Beavertail ADSI browser - it should show you the current AD tree, and from it, you should be able to figure out the path and all.
Or if you're on .NET 3.5, using the System.DirectoryServices.AccountManagement namespace, you could also do it programmatically:
PrincipalContext ctx = new PrincipalContext(ContextType.Domain);
This would create a basic, default domain context and you should be able to peek at its properties and find a lot of stuff from it.
Or:
UserPrincipal myself = UserPrincipal.Current;
This will give you a UserPrincipal object for yourself, again, with a ton of properties to inspect. I'm not 100% sure what you're looking for - but you most likely will be able to find it on the context or the user principal somewhere!