Looking at mapquest and keeping in mind that on my scooter I'm slightly more shy of bigger roads like McGrath here's the route I'd probably consider.

shore dr -> mystic -> butler -> temple -> marshall -> pearl -> medford. staying on the ground level of medford all the way to lambert st and then take fulkerson to binney.

If I were more used to the part of McGrath before the overpass I might take it to medford instead of winding through those back roads, but I think the overpass would feel too much like a real highway unless I had company.