I don't see why everyone is worried about their phone not lasting more than two days... WTH man.
You go camping? How do you get there? Most likely a car - just get a car charger.
Not a car? Buy an inexpensive solar charger or better yet, an emergency charger.
Get another battery...
There's so many solutions...
I too have an Optimus One and although I can get 2+ days out of it with data on (custom rom, 2.3.4 GB) I occasionally go hiking and even an extra battery sometimes is not enough, seeing how I could end up camping for more than 4-5 days in the wilderness.
The car not being around, I've decided the best thing would be to buy a solar charger. It works wonders, yes, it takes 4h-5h to charge my phone completely, but I don't mind, there's not that much to do on a mountain.
I've hiked with a friend who had an extra battery AND an emergency charger. That meant 2 days on normal battery, another 2 from the extra one, and if even 4 days isn't enough, then the emergency charger would be used, only in an emergency ofc.
I really can't imagine a situation where you can run out of battery if you prepare like that in advance.
And really, who goes hiking/camping to stay on the phone 24/7? If you turn everything off and let it idle you can get a lot more than 2 days of it. For example my optimus one uses 0.437 % of battery / hour.
That means over 200 hours of idle time. I'm totally satisfied with that.
Just get a solar charger or an extra battery and turn your phone off when you don't use it. That would be the best way. I don't want anyone calling me when I'm out there anyway.
Solar charges work even if there's no direct sunlight on them, it just takes much longer, but it does the trick.
Also, if you get a solar charger, you can use it for much more electronics and not just for your phone. Also, your friends can use it.
My solar charger costed me 80$ but we were 3 guys paying for it. It's small and we just take it whenever we go somewhere, even if we don't always go together.