If you have a lot of stuff to carry, I think a backpack is a great solution! I personally hate carrying one if it's sunny out (tan lines - I am so superficial
) but they do work great, and I find them to be a lot easier on the back than a shoulderbag. They're easy to slip off and put between your legs on rides too.
If you plan on bringing a stroller, definitely utilize that to hold your bag for you...unless I absolutely HAVE to, I am a no-bag person altogether. I stick park tickets, cell phone, money, etc. in my pockets and call it good. But I understand that's not really possible with little ones.
