I have a relative who has worked at a non-profit facility for children for 30yrs, and after reading the original Wall St Journal article, said the expenses didn't sound out of line at all. And they don't have horses or helicopters.
People forget that this ranch, which lies out in the middle of nowhere, must maintain a clinic/hospital for the kids (imagine the cost of doctors, equipment, etc.) and maintain medivac facilities as well. This is clearly a unique charitable operation to which people donate voluntarily.
I hope you're right and that Imus is a sincere and honest man.