CAKoala,
The trail you speak of across the creek while viewing it from the Pacific Crest Trail, (PCT) passed the warm springs / Indian Campground has two parts to it. The section you speak of that is pasted the warm springs dead-ends at or in Luna Canyon and just a few feet in elevation above Deep Creek itself. Where it dead-ends, you'll see what appears to be a wooden sign, and that is what it is, a very old wooden U. S. Forestry sign. No writing on it, totally worn off or aged.
The other end of the trail you speak of intersects with what use to be old 4-wheel drive trail that is shown on topo maps. That road/trail is no longer in service. Its been bull-dozed by the U. S. Forest Service a few years back. You can still tell the remains of the road yet when viewing it from the PCT. That old trail/road used to lead right down to the warm springs / Indian Campground.
Thee other section the of the trail you were inquiring about picks-up at the Indian Campground and heads downstream right to Deep Creek, (the stream). It then continues and eventually intersects with the PCT.
During the summer months, keep an open eye out for rattlesankes. Over the 13 years that I have been visiting the area, I have come across a few of them in the area.
Keep an eye peeled for poison oak at the hot springs. I believe there's a little on the PCT side and a very short distance downstream from the hot springs.
Lastly, I don't think they exsist anymore, but maybe it's worth mentioning. Years ago there use to be a pack of wild dogs hanging around upstream from the hot springs. I haven't noticed them in a long time, though I did come across one wild dog on the PCT about 3 years during the Willow Fire Closure. He ran when I approached.