Thank you all for answering my (apparently stupid) question about
the boot loader.  I got the 3/60 up yesterday and feel quite happy
about it!

I had a great struggle getting mountd to accept my /etc/exports.  
My server is an Amiga running NetBSD 1.3.  It did not seem to like
the -alldirs option at all. I ended up with explicit exports of
each directory that was needed by the diskless sun3.
Anyway, it works!