Pico Stick or Pico J3 Cub are good choices for a very small area, but you will need dead calm conditions to fly outdoors with them. A Slow Stick or Parkzone Slo-V would be very manuverable as well, but would handle light breezes better. You could go with one of those if you learn to fly at a school yard or football field first then move to your yard once you've got the hang of things. I've seen the Slo-V flown in a small gymnasium before, I'd expect your 1/2 acre is larger than a baskeball court.