Bcharre itself is small enough to walk across in fifteen minutes. The Gibran Museum, the main square and the trailheads down into the Qadisha are all within easy walking distance of any accommodation in town.
For the cedar grove, the ski area, the surrounding villages and any drive over the mountains into the Bekaa, you'll need a car. A few outfits in town rent vehicles, but most visitors arrive in their own hired car from Beirut. Taxis can be arranged from your guesthouse for shorter runs to Hadchit or Bekaa Kafra; ask the driver to wait if you intend to come back the same day.