Rijeka Crnojevica is a small historical town on the ancient trading route through Montenegro. The city is very near the most beautiful part of Lake Skadar. It is worth visiting for both the lake and the old architecture left over from the trader days.
Take a bus from either Podgorica or Budva. If it's not a direct bus to Rijeka Crnojevica you will have to ask the driver to drop you off at the road. Tell the ticket collecting guy well ahead of time (using basic communications, hands & feat, etc.) and he'll be more than willing to drop you off on the main highway. From there start walking and hitch hike. It shouldn't take you too long to get picked up.
There are direct buses to Rijeka Crnojevica from the Podgorica main bus station but they may be hard to find and not run very often.
The whole surrounding area is spectacular. The ancient trade route has long sense been abandoned but traces of the old road are still around (often times grown over with trees). The lake is full of frogs and snakes, neither of which are dangerous. Don't be intimidated by all of the water snakes (literally you'll see hundreds) they are harmless so go ahead and go for a swim.
Camping would probably be best. There is plenty of open space to setup your tent. There is a fairly large hotel near by but presumably it is very expensive.
Buses run from Rijeka Crnojevica back to Podgorica but not very often, so find out when the last one leaves and don't miss it unless you want to go camping.