In my experience, the sand dunes at Alamosa (southern Colo) are so neutral in tonality that an orange filter would be almost meaningless. The only time that an orange filter would be of benefit in that location would be if one wanted to create a darker sky (if the sky is included). I have not photographed at the other locations you mentioned so I have no knowledge of the conditions there.

The solution as I see it is to assure proper exposure and adequate development. I don't know that I agree with giving one more stop of exposure as proper procedure. This is especially so if one is contact printing on Azo or one of the alternative processes. The reason that I take this position is that when over exposure is utilized the film expansion capabilities are compromised when one is developing to a higher DR (contrast). For me film selection is paramount. Not all films will expand contrast adequately to convey in the print the desired result considering the low overall and local contrast that I have experienced at the Great Sand Dunes.

I have used TriX, JandC Classic 200, and Bergger BPF 200 at The Great Sanddunes Ntl. Mon. For my next visit I will use Efke PL 100 or TMax 400. For the aforementioned expansion considerations.

I found that of the three films TriX is the most desirable and the other two films seriously compromised in their ability to expand contrast. However since my last visit I have found the other two films (Efke and Tmax 400) that I mentioned as being more suitable.