Can I go through the state return process prior to submitting my federal return with the online version? I want to check scenarios for itemizing/standard deduction.

You can try to prepare your state returns if the forms are available for the states you need, but you cannot e-file a state return until your federal return has been e-filed and accepted.

And do be aware that information flows from the federal return to the state return, so if your federal return is not completed, your state return will not be complete either.

Understood - thanks!  I meant is it possible to flow from Federal into the State return without actually submitting the Federal return first and just keeping it open?  I would be completing the Federal return first and using that same information in the State return.  Once I determine which deduction method I want to use, I'll go back and finalize/submit the Federal return first.

Yes--as stated, you can prepare your federal and state returns without submitting either one yet.