A few thoughts come to mind. I too like your choice of the LS3-5A's; but be carefull, as they can be difficult to drive (15 ohms). Your friend is an acoustic musician so chances are she will not be listening to a lot of Metallica; so you should be OK with them and a quality receiver. I'm going out on a limb here, but most musicians I know don't listen to the radio very much at all. If your friend doesn't, the choice of an integrated makes more sense.
If a receiver is the way to go, I am tempted to recommend an older tubed receiver such as a Fisher (one listed for sale here for 350.00) or a Scott; but the fact that your friend knows nothing about electronics and is "non-technical" worries me as tubes will have to be replaced; and they will be more prone to needing repairs. They will however give her a "sweeter" sound than most solid state receivers, new or old.
As far as "newer" receivers go: to this day one of the most incredible examples of "synergy" that I have ever heard was the sound that an old college friend used to get from his AR turntable, Advent speakers, and Yamaha receiver; all '70's vintage. To this day, one of the nicest sounds I have heard, sweet, clear and direct. Maybe it was the room and the way he had the speakers set up; I would not have believed it. Then again, maybe it had everything to do with the substances ingested in those days.
All kidding aside, I like the recommendation of an all in one unit, such as the Linn Klassic. Simple as you can get, and as with most Linn stuff, really musical. Good luck.
