I feel for you, I lost my brother's horse in a tragic accident June of 2008, crazy to think it will be 3 years. I personally get nervous about hauling anywhere with my horses, not because i've had issues but because I know so many that have. I know that most full sized horse owners think i'm weird, but my minis all ride loose in our trailer. Horses naturally face the doors/back of trailer when loose because it's easier for them to balance and compensate trailer movement. PLUS I have more then 1 friend who has lost a horse to a misstep while tied and broke their neck/got trampled that kinda stuff.
I'm truly sorry you had to make that decision for your horse, but glad you found comfort in your new one.