Did this hike today for my birthday. Catalina Express will give you a free ride to the island and back on your birthday. I only had a 3:40 window to do the hike from the time the boat stopped at Two Harbors until it left again so I had to hurry a little.
Ran across two guys on the way back, one of whom was cramping badly due to dehydration. I gave him most of my remaining water and some shot blox, but had to keep moving to make it back to the boat on time. Ran across the SAR guys that were on their way up on ATVs to help the two hikers a short time later, so I assume they made it out OK.
I sailed out with my family for the Catalina Yachts Rendezvous at the Two Harbors a year ago (2008). Moored here, and then ran up the Silver Peak Trail to the peak and then came back along a suicide ridgeline that dropped strait down into Two Harbors. Great run and amazing views all the way. The elevation is a but kicker when running.