I've been accepted into a forensics fellowship. I can't answer your question with good certainty, but I can tell you this.
I've been given extremely variable levels of how much work occurs in a forensics fellowship based on the interviews I've had. One program I've seen say they only want fellows working 4 days a week. Those 4 days are regular 9-5 days. No calls.
Other programs: I was told to expect to do around 70-80 hrs a week, and expect to do A LOT of writing & research.
I think there's going to be a strong lack of uniformity on this. Reason why is because fellowships are few & far between compared to residencies, the programs will proabably have only 1-4 fellows & a lot of it will heavily depend on the program director's style.
I'm planning on taking my psyche boards next year-not as a fellow but as an attending. The program I'm entering wanted me for a 2009 position. Although I got accepted into a few programs for the 2008 spot, I really wanted the program offering the 09' spot. They gave me an attending position for 1 year to fill in the gap--at a place I was also very eager to work at.