I almost always carry a paperback. They weigh less than a tablet and don't need to be charged. Once you're done with one, give it away and get a new one. Or trade it.

Everything else, smartphone. I've begun putting a few movies on it (5-6 movies for a 2-month tour). I'll only watch one (usually only half of one) when I have plenty of access to electricity, I'm not in a motel (TV) or hostel (people), I've gotten tired of reading my book, and I'm caught up in my journal, which is not often. As infrequently as I use it to watch movies, the small screen doesn't bother me as much as carrying an extra thing all summer would.

If you're dead-set on a tablet, I'm not helpful, but someone had to champion books.