By far the simplest and cheapest is just to get one or two additional cards for the camera if all you are looking for is space. I'm assuming these are the standard SD type of cards. Maybe go with an 8gb or two which is quite cheap if you aren't too fussy about the fastest possible card speed (only critical if you are into holding the shutter to take multiple photos at once). I always recommend a second card anyway, just to make sure you have a backup if the first card fails for some reason. It's rare these days, but still has been known to happen.

How big are the photos from your camera? If they are 5mb, then you are looking at over 6,000 photos (hope I did the math right), or 600 per day on that 32gb card. That's one photo per minute for a 10 hour day. On a sightseeing trip, I might average 300 or less per day, and I think I'm snap happy.

However, if your goal is a daily backup (getting the photos onto a second device without deleting them off the SD card), then there are devices that can copy from an SD card to a usb stick. However, my experience is they can be slow. You still need to make sure you have enough SD card space, and then also have to have enough USB stick space. Then these devices need either power or batteries (which can mean charging them). Will you have access to electricity on a daily basis?

There are also devices with their own internal memory that can accept an SD card, but these get expensive, at least the last time I looked.

I did the backup from SD card to USB stick one trip. On trips after that, I just ended up taking a laptop. I usually wanted to use it for internet access anyway (still nicer than a tablet for some things) and it just works when it comes to backing up the SD cards.

My wife did a trip recently with just a camera and tablet. I just made sure she had enough SD cards. We decided not to worry about the daily backups. She doesn't have patience for fussing with stuff like that.