I'm going to answer this for a general purpose since I don't have a full idea of where you will use it, but most Sawsbuck sets use Swords Dance instead of Agility. The common set is:
Sawsbuck @ Life Orb
Ability: Sap Sipper
EVs: 252 Atk / 4 Spd / 252 Spe
Jolly Nature
- Swords Dance
- Horn Leech
- Double-Edge
- Jump Kick
Obviously in your case Lonely replaces Jolly, but here is the set.