Remove giblets and neck from turkey; reserve for other uses, if desired. Rinse turkey thoroughly with cold water, and pat dry.
Add water to a large stockpot, filling half full; stir in maple syrup, bourbon, and pickling spice. Add turkey and, if needed, additional water to cover. Cover and chill turkey 2 days.
Soak hickory wood chunks in fresh water at least 30 minutes. Prepare charcoal fire in smoker; let fire burn 20 to 30 minutes.
Remove turkey from water, discarding water mixture; pat dry. Cut carrot and celery in half crosswise. Stuff cavity with carrot, celery, and onion. Pierce lemon with a fork; place in neck cavity.
Combine salt and pepper; rub mixture over turkey. Fold wings under, and tie legs together with string, if desired.
Drain wood chunks, and place on coals. Place water pan in smoker, and add water to depth of fill line. Place turkey in center of lower food rack; cover with smoker lid.
Cook 6 hours or until a meat thermometer inserted into thickest portion of turkey thigh registers 180°, adding additional water, charcoal, and wood chunks as needed. Remove from smoker, and let stand 15 minutes before slicing. Garnish, if desired.