Once the seat of Bosnia's Turkish viziers (Ottoman governors), Travnik is now best known for its sheep cheese, and as the birthplace of Nobel prize–winning author Ivo Andrić, who set his classic Bosnian Chronicle here. It's a pleasant place to spend a couple of hours when travelling between Sarajevo and Jajce.
Jajce bills itself as Bosnia's 'Open Air Museum'. Above an impressive urban waterfall, Jajce's fortified Old Town climbs a steep rocky knoll to the powerful, ruined castle where Bosnia's medieval kings were once crowned. The surrounding array of mountains, lakes and canyons make Jajce a potentially useful exploration base.
In central Bihać, a closely clumped church tower, turbe and 16th-century stone tower-museum look very photogenic viewed through the trees across gushing rapids. But that's about all there is to see here apart from nearby Fethija Mosque, converted from a rose-windowed medieval church in 1595.
Between Jajce and Banja Luka the Vrbas River descends through a series of gorges and reservoir lakes that together form one of BiH's foremost adventure-sport playgrounds. At Karanovac, 11km from Banja Luka by bus 8A, Rafting Centar Kanjon is a reliable, well-organised extreme-sports outfit offering guided canyoning (€25 including lunch), hiking and top-class rafting.