Not backpacking, but sometimes I've carried the Gowland set up and ready to shoot in a boxy but not too large hard leather case.
When I've taken it birding, I usually pull out the rail and put the camera in one pocket of my ScopePak (the other camera being a 35mm with 600/4.5), rail and maybe a lens and a couple of Grafmatics in another side pocket, or distributed among two pockets. Here's what the ScopePak looks like--
If you have a backpack with generous side pockets or that can take add-on pockets, something along these lines can work.
Another mode that I've used is to break it down this way and carry it in something like a Domke with a folding medium format rangefinder as a handheld camera.
You can use a really light tripod for this. For birding, I just use the big tripod that I'm carrying for the big lens. For travel, I have this little Linhof tripod with legs that snap out for very quick setup (the top legs have twist locks for adjustment) and a small Linhof ballhead with an Arca-style QR clamp.
My Gowland lens kit has usually been a 90/6.8 Angulon and 135 Symmar convertible or Caltar II-N (Sironar-N)--all three take 40.5mm filters or Linhof slip-on 42mm filters.