If a gust of wind is enough to excite snaking to the point where the ATC begins to operate on the caravan enough to slow the entire outfit down form the low 50's to 40 mph, strongly suggests the outfit is set up too close to the edge. A gust may cause the outfit to move across the lane but it should not cause an ongoing snake once the gust is past.
It's good to read that post event Outdoorguy is attempting to read the conditions ahead to preempt futre problems.
Given the relatively low onset speed and the continued snake effect causing the ATC to operate to reduce the outfits speed this was not a minor issue, so it's sensible to look at the usual causes of snakes which are usually excess speed, insufficient nose load and or poor load distribution.
Outdoorguy tells us his speed was low 50'smph, His nose load was 95Kg, Both these criteria seem to be reasonable to reduce the possibility of a snake, so why was it so easy for a gust to initiate a snake? The third usual component is load distribution in the caravan.
Outdoorguy tells us he has kept his load low in the caravan which is good, but if that has meant he has had to spread it towards the ends then that is adding to the Yaw inertia which increases the potential for snaking. End loading is generally bad news. The bulk of any load should be added as near to the axle as possible to reduce the Yaw inertia.
View: https://www.youtube.com/watch?v=fWd8ml9mFMo
For that reason I think it is very pertinent for Outdoorguy to review his load distribution in the caravan to reduce any end loading.
It's definitely worth reviewing your loading regime if it make the outfit more resilient to snaking, which will make your towing experiences less stressful.
Good luck.