There is acces to Yellow off of East Cape Horn and West Cape Horn roads. These two roads don't connect (refer to a map). You can walk down or up from either. Yellow is posted immediately above Rt 62 and may also be posted at a house near the creek south of 62. Ther may also be a posted area on the south side of the creek just east of where I-79 crosses.
I've never done that great on Yellow but I have seen and caught trout late into the year. Unless it has changed, I wouldn't expect much in the way of numbers. It is nice water though where it goes from I-79 to Rt 62. There has been mine drainage problems in the headwaters, and work has been done to improve water quality. Hopefully it does. There are some few wild fish in this watershed. Not many at all, but some.
Kev