I live in Maspeth, next to Ridgewood and I commute to 34th Street in Manhattan over the Williamsburg bridge, it's very easy and takes 40 minutes. 80th Ave in Ridgewood would be another 5-10 minutes from where I live.

From Williamsburg Bridge you could take Grand Street (has bike line) to Morgan Ave, (or Bushwick Ave to Flushing Ave) then Knickerbrocker Ave (rough pavement), then Myrtle Ave. There are at least two other options: from the bridge take Broadway straight to Myrtle, but that part of Broadway can have crazy ass traffic in the morning, or take the Brooklyn Bridge then Tillary, Flatbush to Myrtle, but I'm not sure about neighborhoods along this part of Myrtle. My first route would have the lowest traffic though. Sticking to main streets would be faster and safer, some areas may not be very nice, and many smaller roads have horrible pavement. You just have to watch for trucks, you'll be going through industrial Brooklyn and Queens.

If you want THE safest route in terms of neighborhoods and pavement take Grand Street then Metropolitan Ave, then Forest Ave to Myrtle. Although traffic along Metropolitan would be above average and it has some rough pavement for several blocks.

Feel free to ask question, I know this areas well.

Adam