First, your question looks at the issues you're wondering about from an angle that is a little bit backward. Wordsworth pretty much defines Romanticism. One doesn't really define Romanticism then look at Wordsworth to see if he fits the definition. He is the definition. The term came after Wordsworth, and whatever Wordsworth and a few other poets do is now called Romanticism. Wordsworth is a romantic writer so whatever he writes is Romanticism. If you study his poems, whatever you find is Romanticism.
That said, I'll give you an example. In "Lines Composed a Few Miles Above Tintern Abbey," Wordsworth focuses on nature experienced in the distant past, nature experienced in the recent past, and the effect the experiences had on him both times. Romantics emphasized the transcendental (beyond reason, beyond human understanding) in nature. Humans should commune with nature and thoroughly experience and learn from it. This is what Wordsworth demonstrates in "Tintern Abbey."
He writes that the experience he had in this spot greatly occupied his mind after his first visit, and led him to perform acts of kindness, and also led him to a state of mind or a mood. The state of mind is the "sublime." He describes the mood:
Of aspect more sublime; that blessed mood,
In which the burthen [burden] of the mystery,
In which the heavy and the weary weight
Of all this unintelligible world
Is lightened--the serene and blessed mood,
In which the affections gently lead us on--... (37-42)
So you have nature, human response to nature, human contemplation of nature, nature's effect on humans, and the sublime, which is the result of all of the above.
These should help you find elements that today we call Romanticism in all of Wordsworth's writings.