The poem opens by calling the whole of summer a fair, a place of noise, color and drifting from one attraction to the next. The speaker seems to move the same way. "The more I see the more I rove" suggests that curiosity feeds itself: each new sight makes them want to wander further, so looking and roaming become one restless habit.
The middle image, "a dance of loose doors," is hard to pin down, but it fits the mood. Doors swinging open along the lanes could be stalls, sheds or gateways, all inviting and slightly unsteady. The ending shifts the tone. "Thoughts but no fur / found in burrows" pictures a place where an animal might live, yet only thoughts are there. That leaves a quiet sense of absence, as if the speaker has followed the lanes down into something small and hidden and found their own mind instead of a creature. The mood is playful and open at first, then a little solitary and wondering.