Bus travel is inconvenient but possible. There are two main lines with hourly buses from the main bus station (車站; chēzhàn) in Makung. One goes all the way to West Fortress, the other to Fengkuei Cave.
Car & Motorcycle
Hotels and B&Bs can handle rentals (car/scooter NT$1300/350 per day); an international or Taiwan licence is needed to rent cars.
Drivers prefer flat rates to using the meter; most trips cost NT$200 to NT$300. Taxi tours are available for NT$2500 to NT$3000 per day, but it's unlikely your driver will speak English.