You could do it with a raspberry pi and SDR dongle. The pi 3b plus a UPS extension board would do it, giving a real time clock plus off grid power.
KM4ACK Build a Pi software or alternatively HamPi would give you a suite of radio software.
You could control it via VNC viewer installed in a phone or tablet over a kwireless hitspot on the Pi. This would give you a nice waterfall. You’d need to use headphones for listening, or add a small speaker. Pi’s don’t have built in sound cards.
A nice project, but maybe a bit clunky and delicate for the field.
I run a similar set up (without the SDR) for SOTA data modes.