Getting to Elves Chasm via this riverside trail is quite a bit more time consuming than the mileage would suggest. From the beach at Toltec drainage, head west (downstream) following several hundred feet up the riverbank. There is a fair bit of boulder hopping and tough scrambling to do- some people are glad for leather gloves here. Upon entering the Royal Arch Creek drainage that houses Elves Chasm, you have a bit more slippery slithering and climbing to do, but it is all worthwhile.
Elves Chasm is a lovely, shaded grotto with a waterfall. Its emerald colored pool is perfect for swimming on a hot day. There is a cave-like climb up into the waterfall and a spot that people jump from, but this can be treacherous unless you have an experienced guide to point the way. (note: there are reports of high fecal content in the water and definitely a lot of unwashed bodies swim here, so filter and treat if you must drink this water.)
GPS: 36.196327, -112.450754