The OP stated " We had to negotiate a 90 degree turn with very little room to swing into the turn...." Making a extremely tight turn on a high speed bump most likely caused the body of the MH to "rack" as is referred to in engineering terms. Racking would cause the windshield opening to no longer be true and square. This would put a lot of force on the windshield at one of the "out-of-square" corners and could possibly cause a windshield to crack.
Although I might be very upset if this incident had happened to me, I am not sure I would blame the campground owner. I would have to somehow prove the owner was negligent. Very hard in this case.
Ray