You should be able to view your pictures through your digital camera, keep the ones you want and delete those you don't. Or just change cards when one gets full and you can upload photos to a PC later.
I take my digital camera into the field when I hunt. When I go by a game camera I pull the card and put a new one in, then take the SD card with me to my stand and when I get bored put it into my digital camera a view the pictures. The camera even allows me to zoom in on photos that were taken when I'm previewing them.
Doing it that way would allow you to buy a cheap card reader, but still see your photos in camp without the added expense of a viewer or bringing your laptop with you. If you get a reader, make sure your PC has a USB port.
“There are two spiritual dangers in not owning a farm. One is the danger of supposing that breakfast comes from the grocery, and the other that heat comes from the furnace.”