The Prelude is such a long poem you only really need to focus on particular areas. Lines 220-230 are important, focusing on his own thoughts but describing them with natural imagery. Lines 360-400 are to do with the relationship between man and nature and WW uses peronifications and haunting imagery to bring his point across - a mentor-student relationship between the two. This is the main part of the poem. Lines 430-450 are easy to link with Tintern Abbey because it is about the recklessness of youth. 470-475 is another part about the relationship between nature and humans. The last 10 lines are also important because they show how important memories are and what he thinks of being a poet.
If you look at those sections and focus on them, you don't really need the rest of the poem.