Tolborough Tor sits high overlooking the A30 and Jamaica Inn. Bit of a climb from the road (see my directions for Tolborough Menhir) but the views north to Brown Willy are superb.
It is a cairn built into the natural rock of the tor and it is difficult to make out what is natural and what is man-made. Simmerly I can not decide if the cairn was at one time much higher or if it just had a covering. A 'ramp' enters the central plateau from the south east and then you have the large flat slabs sitting on the surface, were they originally covered? and was the ramp the entrance Sabine Gould talked about in his novel ?(see Rhiannons Folklore posting).
There is probably no easy way to reach the barren Tolborough Tor, on the Tolborough Downs. However, one decent way is to start near Bolventor. Cheryl Straffon's guide 'The Earth Mysteries Guide to Bodmin Moor and North Cornwall (including Tintagel)' (Meyn Mamvro - 1993, amended 2000) says "A pathway behind Jamaica Inn crosses the bypass up to Tolborough Downs". Umm, well, I doubt the first bit, unless she means the underpass to the East of Bolventor. There is no obvious route across the dangerous A30 otherwise.
I found a good place to park and start from, at SX182769, just a few metres from the footpath that leads to Tolborough Downs. If heading towards Launceston on the A30 take the turn off for Bolventor but then take a sharp left turn (signposted 'Bolventor Church') and another immediate sharp left (signposted the same). This dead end lane takes you parallel and above the north side of the A30. The footpath is clearly marked about 300m along this road. If you are driving towards Bodmin the principle is the same. Get off at the Bolventor turnoff but don't go into Bolventor itself. Instead imagine you were trying to get on the A30 towards Launceston, and you will see the Bolventor Church signpost on the bend just before the A30 starts again.
This footpath takes you down a few fields (cows grazing) and across a stream to a few houses at Dairywell Hill. Keep to the right of the houses, through a farm looking gate and head up the very steep and rocky track. Carry on until you finally come out into the bottom of the field where Tolborough Tor lies. If you wanted a slightly less hilly/stony walk you might be able to approach (on foot) along the lane from the main road (at SX191777) towards Tober Barton Farm. Don't know where you would be able to park on the main road though.
The cairn is mentioned by the erudite Sabine Baring-Gould in his 1905 novel 'Mrs Curgenven of Curvengen' - but I'm sure it'd be based on his knowledge of local folklore. Well ok, he could have made it up.
[Esther] kept to the heights, now traversing whole villages of ancient circular huts, some within pounds and fortifications, some outside, at what date tenanted none knew. Now and then she startled a couched moor colt or a heifer, or a frightened curlew with a whirr and scream rose from under her feet. Then she made Tolborough, with its cairn crowning the summit, a chambered cairn with a passage leading into its depths, where dwelt the pixies. She passed without fear, the Good People had never hurt her. She belonged to them; they would protect her when taking refuge in their domain, their last refuge from the encroaching plough and the sound of church bells.