North towards Žabljak
There's a good place to hitchhike toward Žabljak about 2.5 km out of city centre where the main street Partizanski Put comes to a fork. Walk north along the street until you cross River Zeta, and you can hitchhike right there at the bend on your right in front of the small market and stands. Locals hitchhike here, buses also pick up here, so if you choose, a bus for Žabljak will come by and you can wave it down. Bus is EUR 5 or 6.
If you get stuck here you can set up a tent by the river just meters from the hitchhiking spot.
Notice - spot mentioned near above hitchhiking spot. But, there's a much more central place where you can sleep, undisturbed, even leaving your tent up to explore a bit. Enter Trebjesa Park (the large green space on the map) besides the Cathedral, and walk on the foot path until you come to the crossing with the road for cars. On your way, you will pass a large water fountain where you can fill up. Take a left onto the car street, and walk 200 or 300 metres until you pass the tennis courts. Take that right, on the corner with the tennis courts. Walk this road into the woods, around the curve, and after a few hundred metres you'll come to a large face of stone running all the way down to the street. It stands out again the forest, you'll know it when you see it. Climb up to the very top of this rock and there's a small patch of flat land where you can tightly pitch a two person tent. There's probably more spots further up the hill if you'd like to explore. It's a nice view of the skyline and no one goes up there, so there's privacy. There are more efficient paths back into the city through the park, you'll find them easily.