Yup, as a former coder myself I like to "see" what I'm trying to build. In the case of speccing out the f/up-seqs I wanted the same ability. After some thinking I found a tool that worked rather well for me: Mindjet Mindmanager
Basically I create a mind map for the sequence. I use the central topic as the title of the sequence and the radiating sub topics as the sequence steps. Mindmanager has auto numbering so it keeps the whole thing sequenced and because mindmaps are read "clockwise" around the central topic, the timing/sequence aspect makes sense too. The actual content for the email or letter or action I simply put into the notes field of the sub-topic. And the best part... in Mindmanager you can chain and link mindmaps together... I've created some very detailed maps of the sequences I've built. Oh yes, the app is drag and drop and mindmaps are useful for loads of things... not just sequence planning.
If you want to see one of mine, let me know and I'll publish it for review/discussion.
Here's a link to Mindjet:
http://send.onenetworkdirect.net/z/33048/CD123109/~James