I don't think you could do it practically unless you put a separate battery and motors in the caravan itself, along with it's own braking system, that is completely capable of driving the caravan while simply using the bike or trike "pulling" it as a seat and a control point. I'd recommend separately controlled motors in each wheel, so you can steer with them as well, because you won't have enough traction with the bike or trike "pulling" it to be able to do that.
If you try to pull, steer, and stop with the bike/trike itself, I'd guess you're likely to get scrubbed and squished at some point, because the caravan is many times the mass of the bike/trike, and you simply won't have the traction needed in many situations.
I've used the SB Cruiser to pull a trailer with a piano on it in one case, and several hundred pounds of dog food in another, but the trike plus me on it weighs at least half of the trailer+cargo weight, or more. Even so, I wouldn't wanna do it at 30MPH. 10-15MPH is more than fast enough with that kind of weight behind me.
If the trailer itself was powered and braked and steered with it's own onboard system, that'd be different, but I still wouldn't wanna haul something many times my trike's weight at high speeds. (25-30MPH+)