There is no reason to try and do everything with a single character--as if you even could without shutting off XP constantly so you don't out level stuff. To me one of the greatest aspects to CoX is in the joy of creating alternate characters (Altitus anyone?). There are so many different ATs with endless powerset combinations that there are still many powerset combos I haven't even tried in over 7 years of playing.
A simple answer to your question has already been address by posters above. But in a nutshell: Explore. Use the Find Contact option. And don't worry about missing any content, as it will still be there for your Alts.
I know this is a bit of a late answer, but I wanted to make that clear, for anyone else who might stumble upon this thread.