As for riding with the traffic...

Riding safely in traffic is counter intuitive. Most beginners try to ride like
pedestrians on bicycles. They tend to try to avoid traffic. They are also
erratic and hence unpredictable and hence can be a danger to themselves and
others.

Forester, a traffic engineer, analyzed bicycle riding and wrote a book called
"Effective Cycling" where he tells you how to ride safely in traffic. I
believe there are websites devoted to it and you can do a search to find one.
Essentially, Forester found that riding your bike like you are a slow motorized
vehicle is the optimum method. He also found that commuter cyclists have the
lowest accident rates by far even though they ride on busy roads in rush hour.
The rates for them are so low that Forester was unable to estimate them (too
small of a sample size). By the way, it is estimated that a cyclist's chance
of getting killed per hour of riding is half that of a motorist. But half of
the bicycle fatalities occur at night with riders whom I believe have no lights
so that means if you are not one of those, your risk is 25% of a motorist.
Also once you get some experience, I would think your risk of fatality would be
about 10% of a motorist. I know, it does not FEEL that way. I feel "safer" in
a car but I think that is a false sense of security.