I think the inside is 18 or possibly 18.5 feet, so there is some more room inside (if we were to rip out all of the shelving and benches that are installed). Our Santa Fe has a back up camera that makes aligning very easy when backing up, so it may not be so bad.
Anyway, we've decided the house is overpriced for what it offers, the small garage just being one of the downsides. The hunt continues...
Thanks for the input everyone!