The ridges formed by the seven Crianlarich Munros provide for excellent running thanks to the tracks hammered out of the mica schist by myriads of boots. However, tackling the whole group of seven together presents a much bigger chalenge than one might expect in the light of its compact nature. Although the as a crow flies distance between the outlying Ben More and Beinn Chabhair is just 9km, the four ridges these hills form are separated by fairly deep bealachs, and the transitions between them are hard going due to rough ground, steep gradients, and no paths or tracks (not even sheep tracks).
[UPDATE 1/7/2016: the route described here takes the hills from east to west; I have added some notes at the end on running it in the oposite direction.]
As such it would be a mistake to underestimate this undertaking. My advice would be to only attempt this round on a day of with good visiblity, otherwise the transitions will require highly accurate naviation by compass and extra care not to fall down one of the many crags that abound in these hills. (On the positive side, an early exit is possible at numerous points along the route.)
The route described here starts from Inverlochlarig to the south of these hills rather than the more usual departure from the Crianlarich side. This has the advantage of a circular route without having to spend time on the A85, plus saves considerable chunk of driving if coming from the Stirling direction.
Start from the carpark just before Inverlochlarig farm (NN 446 185), heading steeply up to Stob Coire an Lochain, Stob Binnein, and Ben More. From the Ben More summit double back to Bealach-eadar-dha Bheinn, and then do a dropping traverse along the W side of Stob Binnein into the bealach that separates Stob Binnein from Stob Garbh (NN 422 226). This traverse is on awkward, complex, steep ground with many dips, frequently wet under foot, with a number of streams running down the side of the hill (offering an oportunity to take on some water; the next good source of running water will be on the next transition).
From the bealach ascend steeply onto Stob Garbh, weaving among the small crags. From here a walkers' path heads, again steeply, onto the summit of Cruach Ardrain, and carries onto Beinn Tulaichean.
From the latter summit drop back into the shallow bealach and from around its low point (NN 416 203) start countouring the corrie to the W, to cross the Stob Glas ridge through a notch (NN 405 204; purists might want to visit the Stob Glas summit, but care needs to be taken on descent, as the ridge ends in vertical cliffs). Descending from the notch, contour the Stob Glas ridge, aiming for the foot of the N ridge of Beinn a'Chroin. This transition is again on complex steep ground, but not nearly as taxing as the previous one; water is available from the stream marked on the OS map.
Pick up the walkers' path on the Beinn a'Chroin N ridge and follow it to the secondary and true summits, and beyond as it descends steeply and with exposure into the bealach separating Beinn a'Chroin from An Caisteal (NN 382 186). At one place this involves an awkward, if very short, down climb, which cannot be avoided, and where outmost care needs to be taken.
Continue onto the summit of An Caisteal, then double back to the flat area around the 900m contour line (around NN 379 190). From here descend into the bealach below Beinn Chabhair via the SW corrie, then ascend the broken grassy slopes of Beinn Chabhair to its summit.
Descend the SE ridge of Beinn Chabhair to pick up the landy track back to Inverlochlarig. The outside seating at the Mhor 84 Motel (on the Balquider junction on A85, once known as Kingshouse), is an excellent place to make good on some of the day's calorie deficit without being too antisocial!
32km / 3,300m vertical ascent / allow 10h
The route runs well in the opposite (W to E) direction; in fact having done both
only three weeks apart, I think I prefer this option: the Inverlochlarig landy
track becomes a pleasant warm up rather than an seemingly never ending finish,
while the gently sloping S ridge of Stob Binnein and Stob Coire an Lochain is
guaranteed to put a smile on one's face even on tired legs. Additionally, the
awkward step below Beinn a'Chroin is straight forward when tackled up hill. The
main disadvantage of heading W to E is that some of the steepest ground is taken
on descents -- overall I think W - E is a better run, but the navigation on all
three of the transitions is more involved and extra care is needed places,
particularly on Cruach Ardrain.
To ascend Beinn Chabhair, beyond the end of the landy track follow the stream
for a bit then aim for the Creag Bhreac Mhor area -- from distance this
appears to be a clearly defined SW ridge with a flattish notch below its more
rocky upper part. Head for this notch and turn the ridge there to pick up a
stream immediately on the other side. Follow the stream to its source on a flat
terrace, and from there weave up steeper ground onto the summit ridge. The ascent
from this side is quite strenuous.
To descend Beinn Chabhair to the bealach below An Caisteal, it is best to retrace
one's steps for a bit along the ridge S rather than heading directly down. There
is a series of small streams (not on the map) that run in northerly direction
across small terraces, and eventually into the bealach just N of its high point;
these provide a reasonable line down.
On the Beinn a' Chroin to Beinn Tulaichean transition, be aware that the stream
heading down in NW direction from the slopes of Stob Glas runs in a deep narrow
rocky incision which is difficult to cross higher up, and which you don't get
to see until literally standing on its very edge -- this is worth keeping in
mind to avoid having to unnecessarily drop height.
On Cruach Ardrain there is only a very faint path on the very steep NE side,
which is very difficult to spot from the summit even when you know it is there,
and even then lot of care is needed.
Finding way down Stob Garbh is, again, more awkward because of not
being able to see much from above (one should aim to follow the NE ridge that
forms the edge of the corrie visible on the OS map, once below the crags, the
way to the bealach below should be obvious). On the upside, the rising traverse
into the Ben More / Stob Binnein bealach is quite manageable even this late in