How to get there:
First, locate the town of Sorrento at the north-west branch of Shuswap lake. Drive around the west end of this part of the lake to the north side. Follow the main road there as it leaves the lake and heads inland. Shortly after crossing a small bridge near location N50.9296, W119.4749, a dirt road named Scoth Creek Forest Road, forks left. What remains is 48 kilometer mostly on pretty good dirt road. The road has kilometer mileposts, you should follow this road to near kilometer 35. Fork right and continue about 10 more kilometer to Grizzly Lodge. Just before the lodge (you will see the building), fork left on a somewhat rougher road. Go right at the next fork and drive up a hill to a distinct hilltop. Park on the side of the road here. This location is N51.17974, W119.29321, elevation about 1540 meter.
Once you are parked (or have walked) to the trailhead described above, you are already on the correct ridge. The short version is: Just follow this ridge all the way to the summit.
However, this is perhaps easier said than done. There is no trail and the first part of this route is 5 star bushwack. You need to get to about 1900 meter of elevation before the hike gets pleasant. From there on, the ridge is quite well defined until a small descent. Thereafter, the ridge turns into a pretty wide plateau. Just follow the highest ridgeline and you will locate the summit with a cairn.
After our climb of Dunn Peak, we stayed in Barriere. The next day forecast was not good and called for an easy hike. We left Barrier shortly after 0500 and drove the good road directly across to Adams lake, then the (also good) dirt road to Shuswap lake.
Going up Scoth Creek Forest Road, we made the mistake to try a smaller forest road that forked right, since it was marked on our map as a possible shortcut. However, this road is a dead end (the map was in error), loosing perhaps 30 minutes.
We parked on the hilltop and started hiking at 0905. Quite a fight to get through the pretty dense vegetation, it was certainly high time when the terrain finally became nice. We had fog and limited visibility, arriving at the summit at 1205. A nice cairn, the sun was not far away and we had some intermittent views. Leaving at 1230, hiking downhill is certainly easier even in the bush, arriving back at our car in two hours at 1430.