I felt the same when I found out about having to keep the nav system but its not the end of the world...
My latest update (short version): It was impossible getting the frame parts that I needed where I live so I ditched the idea. I went today to a diy store and just had a browse...that's when the stupid hat fell off and a light came on
I got a hose/tyre rack and decided I'd adapt it to the nav screen...it worked like a charm
see pic. I'll get into the details later.
Next is the wire loom...