These are the basic careers “most related” to intermediate careers by Trait (i.e. the fastest way to get there by CORE rules):

Chamberlain (can switch at one advance): Agent, bailiff, burgher, messenger
Charlatan(1): thief, gambler, agitator
Investigator(2 advances): Forger, gambler, agitator, envoy, smuggler, student, and thief.
Merchant (1): agent, biliff, burgher, messenger
Physician (2 advances): student
Seer: Mystic
Scholar (2 advances): student
Witch Hunter(1): zealot
Thane (3 advances): courtier dwarf
Duellist (2): courtier, fop, pistolier
Knight (1): Pistolier
Marksman (2): soldier, bounty hunter, waywatcher, wardancer
Outrider (3): soldier, boatman, bounty hunter, coachman, commoner, dockhand, hunter, roadwarden, rat catcher, mystic, servant, witch
Sargent(1): soldier
veteran(1): soldier
Ambassador (3): Courtier, Fop, Pistolier
Demagogue(1): Agitator, gambler, thief
Herald(1): Bailiff, Burgher, Messenger

I did not include the specialist careers such as trollslayer, app wizard, etc.)

Emirikol said:

That's really useful!… and also really surprising in some instances.

So, to clarify, for any advanced career you have to have at least Rank 2 to switch. - So, at 11 xp, you could switch to the ones with 1 xp requirement (by traits).

jh

I think you are confusing the (albeit confusing) meaning of "Advanced Career." 

There are two types of careers: Basic and Advanced. Advanced careers all have the phrase "Advanced Career" at the top, and the one of the following traits: Intermediate, Advanced, Heroic, and Epic. 

When they say you can't transition to an "Advanced Career" until Rank 2, they don't mean one with the Advanced trait, they mean a career with "Advanced Career" listed at the top. 

It's totally confusing because they used the same term twice (and then relying on traits for epic careers rather than actually titling them "Epic Careers").

Agreed.  Technically Intermediate careers ARE advanced careers.

jh