I never tried soloing any instances until I hit about 50-some, and that was to hit Scarlet Monastery for some extra cash/loot... this was long after the Doan drop sell price nerf, mainly just wanted to pick up the Hypnotic Blade since I was getting tired of the look of the Illusionary Rod. So just for the heck of it, decided to do a full clear of the Cathedral (stealth through the rest of it)... took me about 2 hours at the time. Other than that, I had not tried soloing any of the other instances when I was lower level. As a druid I'm more apt to sneak in and take out specific named targets (Maraudon Centaur Khans, Princess pre-1.3-buff, 6 trolls in Sunken Temple, Lord Incendius, Mother Smolderweb).
Onyxia:
Kichebo - 85 NE Druid
Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
Kichebo - 85 NE Druid
Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.