It's about a five minute walk - 10 if it's really icy and you have to be careful. Cut down through the shops, past the internet cafe and you are by the side of the Rila
I,ve never been to borovets, only pamporovo. but dont go by the piste/town map pictures too much, cause there not that accurate and not always too scale. what can look far may only be a 5 minute walk.