Lifou is so big that to really see the island you'll have to rent a car or take a bus tour. The hitching on Lifou is good since there are more cars than on Maré and Ouvéa and almost everyone stops.
An irregular city bus service operates between the main wharf and Luécila weekdays. Shuttle buses (navettes) leave outlying villages for Wé weekdays at 0600, returning around 0930. Other buses operate between Mu and Wé or from Jokin to Wé. Ask about these navettes at the market in Wé around 0900.
Car rental agencies are found near the wharf at Wé, two km north of Wé on the road to the airport, and at Wanaham Airport itself (open during flight times only). Most of the accommodations can arrange cars.
Sightseeing tours arranged through the hotels are an inexpensive way of seeing Lifou without renting a car. Excursions to the north and south ends of the island are offered but the commentary will be in French.