There's the book mira 13" (and 25") and dasung paperlike 13", which is much better than earlier years but even then they have their classic eink quirks (resolution isn't going to be as good as a hiDPI display, they also need some input power to do eink at high refresh modes, etc.). Plus it's yet another thing to carry.

I've had a 'good enough' experience so far with the raised tablet setup outdoors and an extra battery.