Your Wista should have all the movements you'll need in Death Valley. Most locations there will involve some walking, but generally less than a mile in each direction. Thus, my suggestion would be to get a Wista board (or an adapter) for the 210mm, so you can take both lenses. Dust can be a problem there, so QuickLoads or Readyloads would be a real advantage. But, if you take sheet film and holders, a Harrison tent is a real film and time saver. Depending on the size and condition of your existing changing bag, however, you might be able to make an internal support frame from plastic pipe.
On trips of that nature, I prefer using Type 54 (PolaPan Pro 100) for proofs, rather than Type 55, because of the different speeds of the 55 neg vs. proof (if you want both, you really have to shoot two sheets). I also use the Type 54 proofs for taking field notes.
As to filters, I think that's somewhat of a "system" choice. Gels (100mm) are a more economical choice, but glass can be faster and less prone to scratching. I use mostly glass, using 77mm filters and adapter rings for most lenses, and a second, more limited selection in 105mm for monster lenses. But, I already had most of the glass filters before I migrated to LF. If I had it to do over again, I'd probably lean toward a gel-based system.