Is Rumford White Cap the same as Andover Whitecap? If it is, its one of my favorite late summer hikes when the blueberries are in season. Great views and its the closest thing to a blueberry barren in western maine that I am aware of. There are plenty of people who pick there but they dont make a dent in the berries.
My normal approach is from the SW, which has the best chance of being melted out this time of year. Take route 5 north from route 2, take the first bridge over the river, then take an immediate left. Go about 1/4 of a mile and there is parking on the left on the side of a field. The trail is across the street and is not marked for hikers but there may be snowmachine signs. Go straight following an old well built logging road steeply uphill. If in doubt at intersections bear left. At some point the road gets rougher and turns into a four wheeler trail that is wet in sections. After a bit of a walk thru the woods, the trail slabs steeply right up a hill, breaks out on slabs for a bit then runs back into the woods thru softwoods. Once thru the softwoods, you will break out on open slabs, then follow the occasional cairns to the top. Keep an eye out on your left at the edge of the scrub for a very small alpine bog, there are pitcher plants and one other type of carnivorous plant, sundews?.