Good ideas, thank you both. I'm not at all opposed to drinking, just didn't want to risk a reaction to medication if I haven't had it before. I'll try the neck pillow and even using it on my tray. I'm kind of short so my head gets pushed forward by the curve of the headrest part of the seat but I bet the neck pillow would help with that. I may sit on my back pack or something too, both for back/neck comfort if I fit the average height of passengers the seats are built for, as well as giving me leg room for dangling my feet if the seats are low.
We are flying Alaska Air overnight and haven't done that before. The only overnight I've done was on a (since dropped) NW nonstop run overnight moving from Hawaii and it was terrible!! The only good thing was being a direct flight it meant less time for all my pets to be in their kennel cages on the plane. The seats were several inches smaller in both width and the space between me and the seat in front of me (as I later discovered on seatguru.com). I think Alaska is better though. Or at least I hope so.
Robin