The RR2150 would be a nice unit for what they are looking for - I don't think they would go wrong there. On the other hand, you could go the 950 route now, no waiting required, and the new price is pretty inviting. Either route seems like a good approach.

The 950 comes with a simple FM antenna that can be tacked up on the wall or (as I've done) the back of the entertainment center - you don't need an outdoor antenna. Same for the AM antenna, although the AM antenna is a wire wrapped around a rectangular plastic frame. The RR2150 will come with similar antennas, I'm sure. Your Marantz may have come with a similar set of antennas. If not, or if they have disappeared, I suspect you could track down replacements at Radio Shack.