I did a solo overnight of Whitney 2 years ago, and it was the best hike of my life - literally.
Everyone I passed/crossed was very supportive and friendly. I planned my trip well, and just took each step as it came. If I was safe to continue I did (and thankfully I was - with a gorgeous overnight on the summit!). I stopped when I needed/wanted to, rested when I needed/wanted to, ate, drank, etc as I needed and wanted to. I don't hike often alone, but it was definitely a wonderful experience.
