My Milo, who died in January aged 15,went deaf at around ten, totally deaf. I found that he watched me all the time, and followed me everywhere. We developed hand signals, made them quite exagerrated, and he soon picked them up. I think he found life quite boring, so it,s a good idea to try and make things interesting with toys that make them think. And keep a close eye if they are off the lead - we only let him off in safe places like the beach, or where there were no cars, and kept a close eye, though he never wandered off. I'm sure your girl will adapt.
Maybe a comfort blanket that smells of you on the step would help? Good luck
Lesley