There and Back Again has exactly two lore counters on it.
High Alert attached to Ghired.
Steps
At the beginning of your precombat main phase, There and Back Again triggers, putting a lore counter on it.
There and Back Again's third chapter ability triggers, creating a legendary 6/6 Smaug creature token and causing you to sacrifice There and Back Again.
Activate Ghired by tapping it, creating a copy of the Smaug token.
Put either Smaug token into your graveyard due to the legend rule.
When the Smaug token dies, it triggers, creating fourteen Treasure tokens.
Activate four Treasure tokens by tapping and sacrificing them, adding ({2} magic symbol) ({W} magic symbol) ({U} magic symbol) .
Activate High Alert by paying ({2} magic symbol) ({W} magic symbol) ({U} magic symbol) , untapping Ghired.
Repeat from step 3.
Notes
Once you have infinite mana, you may instead use Ghired to copy any other token(s) that entered the battlefield under your control this turn.
Results
Infinite LTB.
Infinite ETB.
Infinite colored mana.
Infinite death triggers.
Infinite Treasure tokens.
Infinite copies of tokens you control that entered the battlefield this turn.