Hi Jage!
That is exactly what I did drilled trough the lot and tapped a thread trough the bars, popped a bolt trough and there you go...
I did a short test drive last night and all is fine, the awning doesn't rattle or make any noise, the roof bars however tend to howl above 50 MPH... Do your rigs make any noise when driving?
As far as the sink is concerned for the moment it un hooks and I slide it into the under-bench sections... the bowl will eventually stow on the LH rear door. I first need to devise a bracket.
As from the beginning of the project everything has to be removable without any modification on the van directly... this is why the whole setup may seem slightly unusual
One of the next challenges will be water stowage... I currently have two 20l water tanks one for fresh one for waste...