MontgomeryMost people reach Montgomery as an add-on from the Boundary Peak climb. I found that once you leave the trail, which ends on the summit of Boundary, the difficulty goes up a step. I dropped down to the left (east side) of the ridge and sidehilled down disagreeable scree to the col between the two peaks. Some folks have recommended staying on the ridgeline as much as possible, but that way didn't look too good to me. Once on the Montgomery side, the climbing became an enjoyable scramble. I stayed on the ridgeline with some detours to the left. The summit pinnacle was cool.
Some people say Montgomery Peak overshadows Boundary in both height and ruggedness. I would say you don't really see that effect until you have summitted Montgomery: from Boundary, Montgomery looks like a similarly rugged but slightly higher peak; from Montgomery, on the other hand, Boundary looks like an insignificant scree foresummit.
The Boundary summit register was full of recent entries, including several from the previous day. The Montgomery register, on the other hand, had received no entries in ten days. Pity, as Montgomery is a very worthwhile climb. On the return, I retraced my route down Montgomery and then sidehilled across Boundary to minimize the reclimbing. Elapsed RT time between Boundary and Montgomery for this very average climber, a bit over 3 hours.
Bottom line? I'd definitely recommend doing Montgomery unless you are constrained by lack of time or threatening weather.