Easiest way (def. not cheapest) would be to use a packaged solar "generator" and some 200w panels. Solar generator is really just a package with batteries, a charge controller and an inverter. Look at companies like
EcoFlow and
Jackery. They are expensive but show what can be done. You can pretty easily do this yourself as long as you understand and accept the risks - take a look at the youtube channel
@jehugarcia for lots of video examples, battery tests, etc.
I have a Solar Generator from Ecoflow and four 350w panels that I use for power when camping in our tent trailer and it works great. When we are home (which is a lot more often than camping, sadly) I leave it plugged into and powering my server rack to reduce draw from the grid. Very happy.
I actually wish it had a good management interface that would allow me to disable taking power from the grid based on time and battery level - i.e., draw only from solar or battery between 3pm-11pm as long as the battery is at least 25% charged. This would let me avoid the usurious "peak" rates PG&E charges during summertime.