@mmn In this specific case, I am unwilling to buy GPS devices running nonfree software, though I might accept nonfree hardware. My concern is not one of privacy or I wouldn't be plotting my hikes publicly.
My issue here is one of usability long term and access to the data. All of the GPS devices I've researched require me to use some sort of proprietary software on my local computer to upload to some proprietary cloud service and requires me to download data from those proprietary black boxes as well.
I'd like to be able to use the device how I like, for as long as I like (avoiding the landfill), and have access to the raw data itself so I can do what I like with it. I haven't yet found a device that meets that criteria.
Finally, I'd like it to be self-contained, mostly so I don't have to fuss with tech when I'm on the trail. I'd like to push record, slap it on my pack, and start walking.
Naturally, I'd prefer second hand devices to interface with Free Software.