[Buzz]

Walter - the body can sit for a very long time as long as it's properly supported with bracing or a wooden buck. Lots of info and instructions available for that. If it isn't supported it can bend or sag in weak areas like the door sills, which could affect door gaps, etc. Another option space-wise is to hang it from the rafters above the frame - again with proper support.
Good luck with the build. There are loads of friendly folks who are happy to share their knowledge and expertise from their own builds, so it should be a fun and rewarding experience.