Mount Marshall is part of the MacIntyre range, but is lower and less interesting than its northern bretheren (Iroquois, Algonquin, Wright). It is a trailless and treed peak. There is a well-defined and semi-maintained herdpath leading up Herbert Brook, and it is actually very nice, with a nice walk up open slabs on the brook for a good portion of the way. Near the summit, recent improvements have virtually eliminated all bushwhacking (assuming you stay on the right route). There is also a very-hard-to-find faint herdpath from Iroquois (Cold brook) pass, but I've not yet been able to find that (although to be honest, I only ever tried this in the winter). There are some reasonable lookouts on the summit.