So before I headed out this year I read thread after thread about long hair on the playa. I have long, straight hair that is a medium to thin in thickness, and that tends to be on the oily side in the default world. So here's what I did, how well it worked, and what I will tweak next year:
Morning I left: Washed thoroughly and conditioned twice with very thick conditioner. While wet I sprayed on a detangler/leave-in conditioner made for kids. Then while wet I braided it into one loose braid (regular, not french braid).
I left that braid in for the 2-day drive there, and then for the first 2 days out there. When I took it out Wednesday afternoon, intending to wash it, I realized why (at least for me) not touching your hair for a few days out there is a BAD idea. There was SO much playa stuck in it, it was super tangled, and I was so glad I hadn't french braided it because I don't think I would have been able to get that out. I didn't have a shower so I used a plastic tub with water to wash my hair, although I didn't use shampoo, only conditioner. I then covered it in detangler spray and hair oil, and combed it out with a wide tooth comb (something I never use in the default world but is a MUST HAVE on playa).
After that I learned my lesson and rinsed and conditioned it every morning, braiding it while wet, and then taking that out and wearing it down at night. At the end of the week it took 2 thorough hair washings to get it clean, and an at home hot oil treatment to get it back to normal, which didn't seem too bad to me. No major damage, no loss of hair.
What I would change: I will definitely bring shampoo next year and wash it with shampoo 2 or 3 times throughout the week. The problem with just using conditioner is that it didn't get out a lot of the playa dust. I'm also going to invest in a pricier, more moisturizing leave in conditioner spray. I will also keep it covered more during the day. Only towards the end of the week did I really start wearing scarves over my hair, and that seemed to help a lot with keeping it clean.