The website for Quincy Cemetery Dept. :http://ci.quincy.ma.us/cemetery.asp
I would call them...obviously Mount Wollaston is a large cemetery and if you don't have specific directions to the graves, your trip would be fruitless. I live near enough to know the area vaguely. I would say it is a safe area during the daytime...traffic could be more dangerous than anything else!
If you go to the MBTA website, click on subway and Red Line and it will show you the stops...if you click on a stop it should bring you to a link where you can see a map of the area. Wollaston station is about 1 and 1/2 miles from the cemetery. For some reason I can't get North Quincy to come up with a map right now...but North Quincy station is about 2 1/2 miles to the cemetery...so I'd say Wollaston station is the winner! Here is the MBTA website/Red Line:http://www.mbta.com/traveling_t/schedules_subway_redline.asp
Mt. Wollaston's address is 20 Sea St...so when you get the map of the Wollaston T stop, click on directions from and then put in 20 Sea St. and it will give you the route.
Anyhow, I am sure the Cemetery Dept can help you with the location of the graves and ask if they can send you the burial records and a MAP of the cemetery with the sections highlighted that you will be visiting...I have had great success with this in larger cemeteries...although I have no experience with this cemetery. Good luck.