I think that the best time to do Cliff and Redfield is the latter part of the winter, or early spring. There is enough snow still on the ground, which evens out all the blow-down; Also, there is a great chance that the trail will be defined and you'll be sure to make it to the top!
The standard route leaves the marked trail at a large cairn very close to the Uphill Leanto. After a few minutes you will come to a second cairn and a fork. The left fork goes to Redfield. Take the right fork to Cliff. After traversing a swampy area you will start to climb very steeply up to the summit ridge. Continue over the false summit, descend into a col, and then shortly thereafter climb to the true summit. The route is fairly easy to follow but take extreme care on the cliffs in wet weather.