I live in Savin Hill now (moved from Southie) and belong to Braintree. I won't be going to the range until later next week at earliest but can show you around. It would be in the evening so the outdoor ranges would be closed.
Next time I'll be there will be Sunday, 12/8 after our Annual Meeting (probably ~1PM) and 12/21 (I'm working as RO that day). If you get someone else to show you around before that great, otherwise you can ping me a day or two before either of those days.