> 1) Does anyone know a way to have a machine automatically check for
> the presence of wired/wireless network(s) at boot and automatically
> choose to use whichever is present?

Well, it's not quite the same, but recently I dealt with a machine
which can have either of two network cards - ex0 or rtk0 - in it and I
wanted to have it use whichever was present.  So I made rc.conf read

case " `ifconfig -l` " in
        *" ex0 "*)      net_interfaces="ex0";;
        *" rtk0 "*)     net_interfaces="rtk0";;
        *)              net_interfaces=""; rc_configured=NO;;
esac

and I hardlinked /etc/ifconfig.ex0 and /etc/ifconfig.rtk0 together.

I gather that in your case you always have the hardware present but
want to use whichever is showing carrier, which strikes me as a bit
harder; whether the above can be adapted to your case is another
question entirely.  But you're welcome to steal the idea....

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