You need room to comfortably manueover, bearing in mind that both your cruising speed and turn radius is greater, plus you would want a buffer on the other side of your furthest flight path to ensure that you are not flying over someone's back yard, or playground, etc etc. Our club has 10 acres and it is not big enough to avoid flying over the neighbors property (although fortunately, that is not an issue..)

However, if you had something like a Reaction 54 (or Boomer intro, or A -10x) you could fly within the same area as required by a Sig Kadet.