Urban Crossings

As a counterpoint to the bike paths/lanes/tracks are safer-
or-not threads, perhaps there is some interesting and useful
group experience with "urban crossings".

How do people deal with crossing through medium to to
large to very large urban areas on long distance tours?

Avoid them?
Skirt them?
Just follow the main route?
Avoid the main route?
Call a cab?

I read a trip journal of a cross-country cyclist who rode
through my not large, but not small city.  He commented
on the traffic patterns and the comfort-level of the route
he took in not entirely complementary terms.

His route was basically the main drag and most direct
route through town.  Though not unsafe,  it was not a
route that many local cyclists would recommend.  And
alternatives, not as direct, but lower traffic could be
been derived from simple city street maps.  Even better,
more scenic and bike friendly routes could have been
used, but only with local cyclist input...

Even smaller cities can pose similar obstacles to
crossing.  The main drag coming into Lawton, OK
from the east loses it's shoulder and gains curbs and
heavy city traffic.  I rode well 'out of my way' just to
get off that street as soon as I could.

Major cities can pose even larger challenges.

What is other people's experience?  Do you plan
urban routes, or just wing it?

Jon