How about doing a larger scale demo and then scaling it up to an offseason in future years? Its a little less hassle/stress but can provide almost the same benefit.
1511 pretty much did this with the Monroe County Fair. They started in 2009 with a general demo where they just invited the other local teams to come and participate. In
2010 and
2011 it grew to a full field and 2-3 other teams coming every day to help demonstrate. Its not a full fledged off-season, but provides nearly the same public appeal with a lot fewer volunteers, and no need for the extras like awards or FMS systems or concessions, etc. It won't become an offseason since their big offseason is the
Ruckus in October, but its nearly the scale with a full field and other teams attending.
Good luck!