I'm asking because there doesn't appear to be a glitchless category even on the category extensions.

yeah there is no glitchless category for this game, or for most of the LEGO games. This is often due to the fact that defining a ruleset for "glitchless" is pretty tricky (is 1p2c allowed? are basic platforming skips allowed? should extras be banned?) Obviously if you want to run glitchless, you are welcome to define your own rules and run it however you like. But be aware that that doesn't mean a category will be created, since we tend to only create "conditional" categories like that (i.e. any% minus some specific thing) if there is a large demand for it, which currently there is not.

Anyway, to answer your question, the structure of the route would depend a little on whether or not Extras are allowed. If you allow extras, then the three currently obtained in any% using no glitches (Exploding Blaster Bolts grabbed in Gunship Cavalry, Infinite Torpedoes grabbed in Into the Death Star and Vehicle Smart Bombs grabbed in Battle Over Coruscant) would still be fast to obtain. With that in mind, the fastest route has some options. As long as you start with episodes 1 and 2 (since you have to play 1 first, and 2 gives you Exploding Blaster Bolts) and end on episode 5 (since it has the longest end cutscene and benefits from all of the Extras), they you will be playing a pretty optimal route. The order of the other 3 episodes does not really matter.

If you are also excluding extras from your definition of glitchless, then it episode 2 does not have to be second, and the rest of the above paragraph still applies.

doesnt episode 2 second still end up being faster because of finish story cutscenes and save cancelling though?