It also does not allow that H and H came to the Dumot some miles upstream of its juction with the Murrumbidgee, getting to that point from downstream of the junction.  i.e. again this is not a travelling in a straight line issue.  In the 1820s and for long after, they travelled where they could, following along the valleys between the ranges, going over the ranges at certain points, as required.  If I went to Tumut from here tomorrow, I will follow the path H and H took.  I will not get to Tumut via Tumut Plains.  If I went to Tumut from Canberra I'd come here first, then still go that same way H and H went apart from a couple of deviations because of the highway.

H and H talk of fires.  This links in with the time of the year it was that also links in with why some travelled at that time (to avoid stuff and get through safely).  It is a Parliament House thing.