Plan to "blitz" the commercial buildings just to learn where everything
is. Go back the second day and visit the ones you are really interested
in.

Do not pick up anything you do not want to carry. It is very tempting!
Do not carry a backpack, it is very easy to overload! (If you decided
to carry things in one of the plastic bags from a vendor, remember to
pick it up after you have set it down!)
Do wear a fanny pack. Carry water, snacks, sunscreen, lip balm. Your
hips support the weight.
Batteries! Either purchase them before you go, or get them at Target or
WalMart. Target you can walk to, WalMart moved a couple miles down the
road.