The speaker imagines going back with someone to an old path and field they once knew. The gate would still be there, but it “will never yield”—the past refuses to open for them. In memory, the sun once warmed them like a golden cloak; in this imagined return, rain and cold wind would be waiting. They would stop to search for the blue stargrass, but it would not be found by the path again. That lost plant becomes a quiet symbol for whatever they shared there: happiness, closeness, a particular time in their lives.
The return is all “if” and “would,” so it stays hypothetical. The speaker already senses that going back cannot recover what was lost. The mood is wistful and mournful, not angry—full of longing and the knowledge that the warmth of the past cannot be reached again.