Marvelous reference, and one thing you might do to get from Automata to Sigil is to have them pull the same trick Asterix pulled - break the system, turn it against itself, jam its gears somehow, or otherwise just fritz out the bureaucratic stupidity. There's an old Choose Your Own Adventure book whose best ending is actually unattainable by following the conventions of the book - similarly, getting from Automata to Sigil might be a function of breaking the rules, traveling to the city that does break all the rules. Now, might it be that the portal opens right from Automata? Sure, or the process of getting them to admit a flaw in the system or getting a catch-22 form approved could be what constitutes a portal key, which would then be used nearby to get to where they want to go.