I bought a small Ameribag on the recommendation of several other ladies who have travelled with them and it worked out great for me. They have tons of pockets for everything; the thing I packed were wallet, camera in it's small case, extra camera battery and card, 4x6 booklet, park map, pen & paper, water bottle, 5 packs of towelettes, and when I went indoors I put my visor and sunglasses in it as well.
I was able to bring it on all rides. You can wear it on your shoulder like a regular handbag or sling it over to wear it in the front or back. It's called a "healthy bag" and they do sell these at some hospitals as well. It's around $65 depending on the type of fabric you select but I bought a brand new microfiber Ameribag from ebay for $34 including shipping!
Ameribag also has a website you can take a look at all the sizes and colors they come in. Good luck!