You should contact the school (e-mail, phone, whatever) and ask them what their average cancellation rate is, and find out if they think it's feasible to reach your goals within your desired time frame. Choosing a good-weather location may be very appropriate for someone seeking a quick upgrade rating, say, adding multi-commercial to existing single-engine comm., in perhaps a 4-day weekend, which might be a pilot's pre-scheduled vacation window. But, that doesn't make that much difference for a long-term training program.
Given your two choices, I'd lean towards Hillsboro too.