Broadly I agree with your ideas.
But think long term; choose the domain that should be doing best; 301 from domain to domain, then no individual 301s will be needed. Then be sure that the unused domain has the content removed.
check several 'old' urls to be sure the 301 works; if in doubt, consult your host (or come back here!). Occasionally stories surface that suggest 301s do not work. In my experience, everyone that gets analyzed shows either a setup error (quite common, as code needs vary); occasionally it's a host issue. I have not heard of real 'failure' in over two years. It's safe, reliable and always the best option.
At this time, use xenu to check that the 'new' domain has good navigation, and build and submit a Google site map.
Search Y! and M$N for links to the retired domain, and where possible, request an update.
Submit the new domain to a handful of Quality Directories.
Rebuild your 404 page to catch stragglers and dead link referrals
Avoid the temptation to do any major rebuilding until the new site has settled down in google, but adding new content is good.
That should keep you busy for a while ;)
[edited by: Quadrille at 11:43 pm (utc) on Nov. 30, 2006]