A turbine rotor blade that includes: an airfoil defined between a pressure face and a suction face; a tip shroud that includes a seal rail projecting from an outboard surface and, formed thereon, a cutter tooth; and a cooling configuration that includes a cooling channel for receiving and directing a coolant through an interior of the rotor blade. The cooling channel may include fluidly connected segments, in which: a supply segment extends radially through the airfoil; a cutter tooth segment is formed within the cutter tooth of the seal rail; and branching segments formed within at least one of the tip shroud and an outboard region of the airfoil. Each of the branching segments may extend between an upstream port, which connects to the cutter tooth segment, and an outlet port, which is formed on a target surface area, so that the branching segment bisects a target interior region.