Westerbork - In WWII a large transport camp was outside this village. Many Jews had been transported from this place. It is now a museum. Also, there is a large radiotelescope.
Borger - The town itself is far from interesting, but in the wider region many people spend holidays there. Many forests are to be found here, with little lakes to swim in. Also, the largest hunnebed of the Netherlands is to be found here. This is not a flat region, by Dutch standards, but quite hilly. Also, a large sheep festival is held every year in Exloo.
Orvelte  - In Orvelte a park with old houses can be found. Very interesting, it gives a glimpse of the countryside in past centuries. It it free to enter the village, but some sights and activities charge €2-5, parking is €4.
It is easiest to come by train from Utrecht, or Groningen (city). If you want to visit Emmen you can take a bus from Groningen (city) or take a train from Zwolle. By aircraft you can get in via Groningen Airport Eelde (IATA: GRQ), which connects the northern Netherlands with (among others) Milan Bergamo and Aberdeen.
Within the state, travel by bus is possible. But the best way to explore is by bike. As there are many little nice villages and small places to visit, it is a good idea to go exploring by bike. Many bikeroads have been build.