How do the allusions support Bradford's central idea that the Pilgrims endured a difficult journey into an unknown
wilderness?

From Lines 78-109 Bradford's story makes allusion to the bible when he talks about the difficult voyage the pilgrims had to take and how he got the "promised land", he also makes an allusion to the bible when the apostle Paul helped spread Christianity

Explanation:

In "Of Plymouth Plantation" by William Bradford we can see a constant use of biblical allusions as many of the Puritans did, writers used this literary device to make the idea more important since it had the divine intervention of God, There is a very strong connection in his writing between the event in The Pilgrims lives and the hand of God.