Piece of cake. Loosen the axle nut. Jack up the bike with a floor jack under the emissions shelf (the funny little fin under the seat, behind the muffler). Remove axle nut. Remove brake arm nuts, the one on the linkage and the one on the support rod. Tap axle out with a dowel, yank out dowel, wheel should fall on your toe.
Brake plate lifts out, flip it over, grasp both shoes and flip them toward the middle. Remove spring, put everything back together in the reverse order. You can/should apply a small dab of grease where the brake shoes touch the mounting pins, and a bit more on the axle shaft.
It actually takes longer to type than to do. While the bike is still on the jack, spin the rear wheel by hand and adjust the shoe travel (tighten the nut on the brake linkage). Once the brake feels right, take it for a test ride, get the bike p to 20 or so and stop with the rear brake only. Do this a couple times, readjust the linkage nut, check the axle nut tension and call it good.
EBC organic brake shoes are $46.95 at Bike Bandit.
Stock shoes are $40, plus $60 labor...