I basically picked the Vitalyte because it appears to have less sugars than most and because I tend to bloat on anything with high sodium. It also has a pleasant taste, while I've found several other brands I've tried quite obnoxious. YMMV, of course. Note that I dilute it to half of what is recommended, too. It does work for me, especially in hot weather. One time last summer when I wasn't using it, I was so tired when I got to the car that I didn't think I'd be able to drive home. I mixed up a pint, drank it and within an hour I felt fine.
I certainly don't want to minimize the importance of stretching, and daily exercise, though! If you're going to go for a vigorous hike when out of condition, you're going to be sore! For the last three months I've been doing extensive stretching 3-4 times a day for my plantar fasciitis (which is now a LOT better). I suspect that (because I had a severe case) I'll have to keep doing those stretches for the rest of my life, just as I have to keep doing knee and lower back exercises. However, back in the days of my pregnancies, I'd experience leg cramps the last 2-3 months which the doctor specifically said was due to low calcium. There's both a dietary and exercise component here.
Re the dried banana labels--potassium is not one of the items that the government requires on the label. Just because it isn't listed doesn't mean it isn't there.