If you really want high quality provisions... I would also recommend checking out the "Ample Hamper". Not cheap but REALLY good.
http://www.amplehamper.com/
Even if you do most of your provisioning from Bobby's or Riteway...they are worth a visit for some treats.
Since it seems you will be in Roadtown, I will also suggest two other things:
1. Visit the Roti Palace for lunch. If you've never had a Roti..you will be in for a treat. (Try the boneless chicken!)
2. If you enjoy British food and treats...curries, jams, pasties, bangers, scotch pies etc. try the Best of British shop downtown near the water.
Have fun!!