The 100 bus and 325 both bring you around the corner from Wright's Tower. The 99 brings you to Spot Pond.
You can take the T to Oakgrove, and then walk. Depending on where in the park you want to go it will be more manageable. Also, use google maps public transportation to find a bus that might drop you off even closer (probably from Malden Center).
There are buses that go by. Not sure if they come from Brookline.
Not that im aware of no,public transport
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