Some things I've found:
createAccount - There's a lot of different hogwash in the documentation and samples, all of it wrong in one form or another. The icons parameter should actually be setup thus:
"32x32": Mojo.appPath + "icon32.png",
"48x48": Mojo.appPath + "icon48.png"
Mojo.appPath is required, and then after that you link your icons from wherever they are in your project.
Accounts Linked to Email - There was some initial confusion because when I created an account with domain of "idunnolol" with username "dlew", Palm would give me the option to log into an email account "email@example.com". The fact of the matter is, Palm always thinks the account you create is linked to an email, even if you're just using for email. Sorry! You'll just have to get over this.
updateEvent - The documentation would have you believe that it takes two parameters - event and trackChanges. But when you do that, you get the error "ErrorGenericInvalidParameter: Missing Required Parameter: event.startTimestamp". What you really need to do is setup your event as the entire parameters. I have no idea where trackChanges could go (but I don't use it):
Besides those three things, I found that the code was much easier to work with if I setup a chain of onSuccess(), onFailure() calls that always guaranteed that I had a valid account and calendar. When I try to create a calendar event, first it checks that I have an account, then it checks if I have a calendar, and creates them if it doesn't exist. It's nice to have this built into your implementation because users can (at any time) delete your account if they feel like it.