Hey Mike,
we (newly founded rc-club) built a improvisational track till we get all the permits for our permanent track.
Took a few photos, maybe there's some inspiration in there for you.
That crossover jump is pretty nice, might want to watch how you build your ramp though. The way we did it, with my B4 I sometimes over-jump by 3-4 times what would be required to clear the gap "by accident".