Hey when I have time to try to help, I'm in.
PI micro-SD card backup: how I and many others do it: remove SD card (see below for comments on how to do that nicely), put in your windows computer. Download free program ImageUSB (
https://imageusb.en.uptodown.com/windows). it will copy a complete SD card to an image file you store on your windows computer... if you need to make a replacement SD card, you ue it to WRITE to a new SD card the image you previously saved.
AS for moving youur CM15 to another room, no problem! Your PI is only tied to a power cord and communicates via wifi to your network. So move it anywhere you have wifi connection! Of course beware that 1/2 your house is on one side of the 220v , so your results may vary.
As for removing your SD card from PI: You SHOULD power down your PI at leas before removing it... How? when you quit the putty program and are back at the putty pi command line, type in "sudo POWEROFF" IIRC _ may be wrong. Wait for it to shut off (10 seconds or so), then ull SD card.