Do not sledge hammer the rotor. The lug bolts are pressed into the disk, to remove the disk, remove the lock out hub assembly, then purchase or borrow a socket that will fit the spindle nuts inside. The socket will look like a piece of pipe with 1/2 drive on the back, and small square pieces welded to the inside of the front section of the socket. Anyway it fits the spindle nut that is round with keyways on notched into it.
Ok once you remove the spindle nuts, then the rotor should slide off the spindle. The only truck that uses a 2 piece rotor is the 4x4 dually. Check the bearing while it is off, and replace the seals.
I am not the biggest and I am not the best but I fall somewhere comfortably in between.