Upgrading from 6.x to 7.x

[Warren Liddell]

I have read a lot of ways an issues with upgrading to 7.x from 6.x ... the 
main place that seemd ot have someewhat simple guidelines was 
http://people.freebsd.org/~rse/upgrade/freebsd-upgrade-6x-7x.txt  .. however 
i wanted to know if that is the most simplest an efficent way to go about the 
process ?

The reason i ask as this machine is a production system and cant afford for 
any down time or in theory anything to break to cause down time in the 
system.

Any thoughts etc are always welcomed.