Pondering Travel Packing

In my years I have learned that packing light is the way to go, however, I am not the best at doing so. I'm battling a packing list presently. I will away from all my "stuff" for 5 weeks... that's a long time for me to not have at least 20 shoe choices. So I'm trying to make a list of essentials and things that I think are appropriate for all the jobs and activities I will be doing. If anyone has any suggestions or ideas... please fill me in!

I'm pretty low maintenance, but also a make-up/skin care monger. So I will only be bringing a small make-up bag and a sample of my skin care regime. Let's hope I don't came back looking freakish! I am hoping to manage smelling good and keeping clean with only a bottle of tear free strawberry breeze 3-1 kids shampoo. It was also suggested to me that it may be fun to do some shopping at the local store and see what the Ticos use to shampoo rinse and repeat. :)

Clothes: easy and breezy is my idea for packing. cotton dresses. skorts and t-shirts. capris and tank tops. I need to be dressed "conservatively" while working. I think I've got most of my bases covered there, since that's pretty much what I wear to work anyway. On weekends I will want to have beach wear and something flirty in case I go out on the town. And I don't need to bring 5 weeks worth of clothes of course, I will have the option of washing them, so I'm really hoping to keep everything to just ONE suitcase.

Shoes! Shoes shoes shoes are going to be the toughest choices for me. I have to bring sneakers. I am also bringing my Chacos. I need atleast one pair of flip-flops. What else should I bring for footwear? Am I going to need "going out shoes in Costa Rica?" Do people even get dressed up to go out dancing, etc?

I am bring a camera (obviously). I'm bringing a pacsafe to keep my belongings safe when I'm staying at hotels/hostels. I have a purse that can't be slashed. I'm bringing my laptop and a digital photo frame (so that I can share pictures with all the people I meet at work).

I'm really going to have to edit. I am planning on packing starting Oct.1 so that I have time to edit everything down and get it all in ONE BAG.
If you've travelled to Central America (or something similar) and have some suggestions for things to bring that might be handy or that I won't be able to find there, please let me know.

Thanks,
Lori