We ended up converting an entire ASP.NET 1.1 web site to 2.0 in under a week. It turned out to be easier than I imagined - I estimated 2 people for 2 weeks, and it looks like it will be 1 person for 2 weeks.

I don't want to understate how many problems there were. In the project as a whole, there were THOUSANDS of warning and error messages after the conversion wizard that done its work. But because of the duplicate nature of these problems, it was usually a search and replace job to fix them. One search and replace could fix 50 warnings at once. And even the ones that had to be fixed manually, I could usually just F3 from occurrance to occurance and paste in the corrected code.

The site is now up and working. There is still a lot of testing to do obviously, but I am extremely happy that it has turned out so well.