Communication and Travel

I was just rereading full thrust and more thrust with an eye to how
solar systems would communicate with each other and exactly how long
would it take to go from system to system.
John hints that there might be some form of interstellar communications
in his senarios but doesn't actually say so.  The communications might
be in system.
If there is no interstellar communications, then the fastest way to get
word out is a small fast ship. (Lots of work for the scouts).
How fast could a scout get to the next system.	Consider a scout going
from Alpha Centari to Sol (a distance of over 4 light years, I think).
The ship would have to make 3 or 4 jumps to leave the system, 5 more in
deep space, then 3 or 4 more coming into the solar system.  A total of
11 to 13 jumps (say 12).  At a minimum 6 hours between each jump, 3 days
(really pushing it)  A normal military ship would take about 12 days (1
jump per day) and a merchant ship 24 to 36 days (say 30).
This means a month of travel to one of the closest worlds.   If human
space is about 40 light years accross, thats 3 months travel at a normal
pace.  And that if the ship doesn't make any stops.
Convoys and fleets will take longer as they will need to periodicly
reform.

Tim