Question bout migrating from 4.X tree to 5.x or even 6.x

[Robert Yoon]

I am planning on upgrading from the 4.x tree to the 6.x tree.
I have been reading online and have found little or no reference
information.
I would like to actually do this without a make world scenario, and have
read some info bout booting off a usb device with 6.0 on it and copying
stuff over.
Anyone know of or heard bout this by any chance?

Also what recommendations would you make if you were to upgrade from 4.x
tree to 5 or 6?
I know most of you will say start from scratch, but I dont have that
luxury.   Please help