Jim,
What many of us do is type out a long reply on a Notepad or Word processor document. Then just copy and paste. That way you have it saved.
You might have to hit the enter key 2x to leave spaces between paragraphs. The spacs don't always copy correct. But it sure is better than having one go *poof*.
Another hint...if it's really long, split it up into a few posts. It makes it easy for people to read.
If you need any help, let me know. Welcome.