Bootstrapping a 64-bit environment starting with a 5.2.1-RELEASE CD set

[Conrad J. Sabatier]

I hope this isn't considered off-topic for this list (as in, more appropriate
maybe for the questions list).

I just bought a new AMD64 system yesterday, and I'm wondering how to go about
building a complete 64-bit environment, starting from a 5.2.1-RELEASE install.
The initial install of gcc won't support the -m64 option, although it does seem
to support all the other CPU-specific options.

What /etc/make.conf options, kernel options are recommended and/or discouraged,
and how many builds will be needed in order to bring up the final environment?

Are there any potential "gotchas" to beware of?  Are there any good online
sources for this information?

I do very much appreciate any advice.  Thanks!

-- 
Conrad J. Sabatier <conrads at cox.net> -- "In Unix veritas"