Fave place is probably Sheepstor and that general area as I grew up walking there. Sheepstor has everything but the entire Burrator area is fantastic. Dem'port Leat, Leather Tor/Sharpitor. I like going up the Plym east of Sheepstor. But the bit N of it is cool too. Cramber/Coobeshead Tors, Crazywell Pool.
Further east The Dart is nice from New Bridge upstream. Usually higher up though above Holne, Venford Reservoir/Bench Tor towards Hexworthy & N to Laughter Hole. Bellever Tor is a good spot. Further N to Postbridge the walk up the East Dart is great to Sandy Hole.
Then the Tors above Two Bridges going up the West Dart are good too for access to the North.
I don't actually like the N as much but the high tors are there and the western fringe is great, from Okehampton going south Gt Links/Brat/Hare Tors and Tavy Cleave. Then in the middle you've got Fur Tor.
The area west of the B3212 to Princetown is also good. Foggintor Quarry is a great place and good for a swim but you need to wear shoes, the blasted rock is razor sharp.
the NE and the Teign is also pleasant.
Too long for your timings probably but google the Perambulation of Dartmoor as a route. It's the medieval circular route taken by the Kings household to check his holdings.
Really you can go just about anywhere and enjoy it. There is usually something of interest, on the high ground just go Tor to Tor and pick up the bits on the way. Stone circles and rows are often very impressive. Cairns, circles and cists can be too but may be harder to find. on the fringes and in the valleys you get steep sides and fast rivers and the odd pub and cream tea.
Aplogies to the places I've ignored, in particular the Walkham and Mis Tors, Staple Tors & Roos Tor!
