you might want to consider to keep a copy of your user@dom0, /etc and /usr directories to a user@dom0 too.
So, in a case when qubesd doesn’t work but you are able to boot to dom0, no other qube works, so your out-of-dom0 backup of dom0 is worthless, unless you potentially compromise it by accessing/mounting the volume externally. This way it’s safer and faster too, I’d say.