Thanks for the help, everyone.  I need to do some trouble shooting 
and have some more low-end-of-the-learning-curve questions.

I can't ping the NetBSD box from within the LAN, which tells me I've 
munged up the configuration somehow.  My guess is that I've failed to 
configure the LAN side of the interface with the "inside" IP address 
so that the other computers can find it.  I have configured the other 
computers manually to use the NetBSD box as the gateway in OT .

Erik's note indicated:

>Unless you have the dhcp client enabled in rc.conf, your IP address
>under NetBSD is assigned via /etc/ifconfig.sn0 or /etc/ifconfig.ae0

What's the proper syntax for this?  My ifconfig.sn0 currently reads:

           inet sugaree netmask 255.255.255.0

I didn't see this directly addressed on Bob's site.

Should I create an /etc/sysctl.conf file (this was mentioned on 
OpenBSD's site about setting up rdr, but sysctl is in /usr/sbin on 
NetBSD; if I need a *.conf file would it go in /usr/sbin)?  Do I need 
to enable forwarding with "net.inet.ip.forwarding=1" in sysctl.conf 
(as per the OpenBSD site)?  Bob N's setup Web page mentions  doing a 
"/usr/sbin/sysctl -w net.inet.tcp.rfc1323=0" - is that necessary?

Thanks so very much for all the help.  It's truly amazing what NetBSD 
can do (in the nads of someone who has a clue about what they're 
doing, anyway).

Obviously I need some reference materials about system 
administration.  There's a logic to this system that sort of escapes 
me, since I'm used to a decade and a half of Macs which offer minimal 
configuration options.  What would you recommend as being the closest 
to NetBSD (since there aren't any books specifically on that, yet).