Swarth Howe is a pretty easy place to visit. It is just off the A171 and has a carpark on the opposite side of the road.
Accessibility is a completely different issue, the barrow is lost in a pretty much continuous dense thicket of gorse. It is possible to pick a path through the gorse and only come away with minor scratches but to be honest with you it's not really worth it. You'll spend a good half hour stumbing around to be rewarded with a fairly non-descript mound. Definitely one for the enthusiast.
The stone row is a different matter.
As you walk up the gorse lined track from the A171 to the wireless station, you'll find Swarth Howe on your right and the stone row on your left.
It is possible to find a gap in the gorse and make your way to the stones but I would advise that you walk a little further up the path to the gateposts and then backtrack along the edge of the woodland. This will bring you to the first of the stones. Once you've found the first stone just cut into the trees and you'll find the OS pillar and beyond that the second stone.
One point you may not appreciate if you are approaching the site from the north along the A171 is, that at 264m the Swarth Howe site occupies the highest point on Northern Margin of the Lower Esk valley and can be seen from many points to the south of the Esk as well as from a decent radius of coastline. This place was deliberately chosen and in my opinion is well worth a visit even if just to appreciate the topographic aspects of the site.
I had planned a circular walk from the carpark at NZ843088 through Hutton Mulgrave Woods and then back along the path at Moorgate Farm checking out the cairnfield and standing stone at NZ825098 but unfortunately the path from the farm no longer seems to exist and with no one around to ask I had to back track through the woods.
With reference to Rhiannon's comments about Robin Hood's Pillars.
These can be found at NZ918095.
Stanhope White describes them as
"two saddle-like stones, round pillars with small mushroom caps; the rim of the first is engraved Robin Hood Close and the other Little John Close......
It is not improbable that these two stones have replaced two Bronze Age standing stones; they would have attracted tales of Robin Goodfellow; when Robin Hood began to appear as a folk hero his name replaced the earlier leaders name, and no doubt some good burgher of Whitby replaced the ancient stones with these more decorative modern ones!"
Standing Stones & Earthworks on the North Yorkshire Moors.
Robin Hood, or Robert Earl of Huntingdon, of whose exploits, at the head of his merry outlaws, all the world has heard, died in 1274. He is said to have been the founder of "Robin Hood's Bay," near Whitby. One day, standing on the top of Swarthoue, the highest tumulus in our vicinity, he resolved to build a town where his arrow should alight, which he then shot towards the coast where the maritime place above named, with its 1200 inhabitants, is now situated, although the distance direct across the country from Swarthoue is at least six miles!
p114 in 'A glossary of Yorkshire words and phrases collected in Whitby and the Neighbourhood. By An Inhabitant. 1855. You can read this on Google Books.
The Inhabitant also mentions some stones of indeterminate age connected with Robin Hood, but maybe they're gone now?
Robin Hood's Pillars - two rude stones, between three and four feet high, a mile to the south of Whitby Abbey, which tradition asserts as marking the places where the arrows of Robin Hood and his mate Little John fell, on a trial of archery from the top of the abbey, after they had dined with the abbot. They are in separate fields, which are still called Robin Hood and Little John's closes; but John outshot his master by a distance of one hundred feet, according to the position of the pillar assigned as his.
THOMAS CHAPMAN, Esq. communicated an Account, by Mr. SAMUEL ANDERSON of Whitby, of the Opening of an ancient British Barrow, known as Swarthoue.
This Barrow stands on a lofty ridge of land, four miles from Whitby, and eighty yards from the high road leading from that place to Guisborough. It is the centre one of three Barrows having a direction W.N.W. and E.S.E., and is the largest of the ancient British Tumuli in its immediate vicinity.
There has been at one time a line of large stones pointing from one Barrow to the other, but only two of these now remain. On these are several markings, corresponding with those on a stone found within the Barrow.
The circumference of Swarthoue is 280 feet at its base. An opening was commenced on the N.W. side, removing a section to the centre, and going down to the surface of the ground on which it is based; the cutting was then continued in a westerly direction, and, after reaching the surface again, traces of an interment were discovered, with an urn of the usual character.
A further search led to the discovery of two spear-heads of flint, and two ornaments of jet; one of them a ring punctured with two holes as if for suspension, the other with one hole only.
On the N.W. side were discovered traces of dark matter, apparently the decomposed remains of a human body which had been buried entire. Further excavations were proceeded with to the south, and to the eastward, when a stone flag was found to cover a vault measuring internally three feet by two feet, and about sixteen inches deep, the sides being formed of two stones each, and the ends of one only. Within this Cist or Coffin nothing was discovered save a little charcoal and some dark decomposed matter. A little further a portion of a bone Pin, and a small Urn embedded in charcoal, and calcined bones, were found.
This Barrow had been laid slightly concave, or "dished" at the top. It had three walls running across it from north to south, about five feet in length and three feet apart, four feet in height and about two feet thick, many of the stones being so large that they were as much as two strong men could lift. The only object of importance found within these walls was a marked or carved stone of a character similar to that already mentioned.
"East and west of the OS pillar are the two standing stones that Anderson believed to be the survivors of a row between the two barrows. Both are blocks of Jurassic sandstone, 1m high, their upper edges weathered and fissured by deep irregular pits. These must also be the pair of 'Druid Stones' marked by Robert Knox west of Swarth Howe (Knox 1821; 1855)."
A 19th century antiquary:the excavations and collection of Samuel Anderson
by Terry Manby
CBA Research Report 101
"A line of large stones on Dunsley Moor is said to have run between the Swart Howe and another barrow. Two of the stones are further stated to have been carved in a style similar to that of a stone, now lost, found within the Howe which contained a burial of the urn period. Knox describes four stones about 3 feet high at this site, which formed an oblong."
Early Man in North-East Yorkshire