Like others glad you and the family are ok…
Your advice is good and something everyone needs to heed… no amount of experience makes up pulling these trailers with mid axles with antique braking systems safe for those conditions (even with chains)…
I have pulled trailers in snow for a living, but when it came to camping trailers, I have pulled in the snow only long enough to find a place safe to pull off the road to wait it out…worse yet is the black ice that takes any control the driver has away…
We wish you the very best in the future while you count your blessings today….