For these kinds of situations, power banks are great. I get the impression that they're not very popular in North America (dunno, haven't lived there for a while), but they are everywhere in Asia. I just bought a new one that gives me over 10k mAh. Enough to charge quite a bit of both my phone and iPad (and it comes with both USB and Lightning connectors to boot). For a long weekend or vacation, it's well worth packing these things, it's not like they're cumbersome or heavy either. About the same size and thickness as my phone for 10k more mAh.
North American here. Power banks are commonly available (ie, present in almost every electronics store), but I am one of the few people I know who regularly has one.
>10k mAh
Interesting choice of units.
But, I really get killed on long weekends or vacations. My usual routine is broken, and I frequently find my iPhone running out of charge. Hardly the end of the world, just a minor annoyance.
As noted elsewhere, having the juice to get through a full day, even with heavier than normal usage, would mostly alleviate the problem. Of course, if that's going to cost me another $100 or turn my phone into a phablet, then I'm not intereted. :)