HI Shawn - thanks for posting. I know you have been chatting a bit with Josh, just wanted to add a few more tidbits on this topic. I think your suggestion is a really good one and we will definitely add that "clip" idea to our list of potential enhancements.
I did want to be sure you were aware that you can get a summary report for your Area of Interest (AOI). The first way is to use the "Landscape Summary" workflow and upload a shapefile and use as an AOI (see screen capture below). The auto97th report that is generated (if you have an AOI identified) will be for that AOI. We have it on our list to allow users to use an AOI in the Landscape Fire Behavior and Playground function, we just haven't gotten to it quite yet.
Also the idea of using an Landscape extent that is something other than a box is also on the list - we have had other folks suggest this as their project areas are up against a lake or something that has an irregular boundary that they don't want to be included in their landscape extent.