I have hair down to my butt (well it would be if straight, it bounces up to lower back height) and I think keeping long hair detangled and unflattened at night is actually easier than shorter hair. If I've just showered I put it in a scrunchie on top of my head (a la Pebbles from the Flintstones, what some people call a pineapple) or if it's dry I just flip it up over the pillow. Voila, I can toss and turn and the hair doesn't get affected. You could switch to a statin pillowcase for even less frizzing, but it couldn't be simplier.
3B, No Shampoo Since 2002, Brown w/ Redish Highlights, Butt Length when wet
Routine:"Shampoo": DevaRed No-Poo (Occasional Low-Poo), Detangler: Pantene Pro-V Red Expressions (Wide Tooth Comb with detangler in), Leave-in: Lucky Kentucky Conditioner, Gel: LA Looks Frizz Control (Plop with leave-in then Gel then put it on the top of my head Pebbles Flintstone style with a bead scrunchie. Wrap with Micro-Fiber Towel for a while then take towel off and go to bed.)