I'd be curious which is the best option to charge a phone. I don't mind stumbling around in the dark, but am sure my kids would want their cell phones charged.
Save me a trip to the library to charge phones.
IMO, a decently sized battery bank (check for phone compatibility) that you can charge before you leave, top off with the sun and charge phones multiple times is a really good option.
As for best kinds, I don't know- I trolled Amazon and checked for price and user ratings, ended up with a 14W panel and a 13,000mAh bank for about $45 total. Portable panels and battery banks keep getting cheaper the longer you wait...but summer's coming.