Depends on what you're looking for..........personally I would stay at The Peaks of Otter north of Roanoke (about milepost 86 on BRP). The lodge is spartan but clean, no TV, no phone, no clock radio, mostly no cell service, decent restaurant on site just make sure to arrive before it closes, dynamite views but of course you may be getting your fill of fabulous views by then. Roanoke/Salem area offers plenty of lodging choices. I'm not familar with hotels in Lexington. As a side note, if you were to stay at the Peaks of Otter, the National D-Day Memorial in Bedford is about a 20 minute drive. If you have any interest in WWII history, this should not be missed if your schedule permits (lots of TA reviews incl mine and I'm usually unwilling to spend time anywhere except on the trails) . Even if you stay in Roanoke, this could be a convenient stop, not so if you chose Lexington.
Enjoy your trip.