To answer my own question I later realized that I didn't need AvalonDockHost as later versions of AvalonDock allows for MVVM by use of the AnchorableSource, DocumentSource and ActiveContent properties as described in the AvalonDock.MVVMTestApp.
<avalonDock:DockingManager x:Name="dockManager"
AnchorablesSource="{Binding Tools}"
DocumentsSource="{Binding Files}"
ActiveContent="{Binding ActiveDocument, Mode=TwoWay, Converter={StaticResource ActiveDocumentConverter}}"
Grid.Row="1">
I haven't managed to get everything working as I'd like yet as my layout is quite different from the VS enviroment that AvalonDock is trying to recreate. But I must say I think this is a great tool!