I-270 Commuters Seek Advice

Here are a couple of questions that came in from commuters taking new routes to work. I'm seeking your help in advising them.

Dear Dr. Gridlock:
We just moved to Gaithersburg and will start commuting down I-270 toward I-495 in the mornings. Can you tell me what time the morning rush hour generally eases up? If you need to reach I-495 by 8:45 or 9 a.m., what time would you routinely have to plan to get on the road at exit 9?

Dear Dr. Gridlock:
Can you advise the best route to get between Rockville and Hyattsville? Would you advise taking 495 or using back roads. This will be Mon-Fri at the peak morning and afternoon commute times. [Shady Grove Road is the exit off I-270 that I take to get home. I will need to get to Prince George's Plaza for my new job, to be more specific.]

On this second one, I'm inclined to say, Stick with the highways on most days. There will be congested zones along the way, but over the course of the entire trip, I-270 and the Beltway are likely to be as good or better than secondary roads. What do you think?