The Hotel for Desert Ops Phoenix in 2012 was the Tempe Holiday Inn Express. Website
It is located at the Baseline Rd.exit from I-10, just east of the freeway, and just south of the junction with the US 60 freeway. This location is close to a number of the host railroads and central to all.
Rooms feature wireless internet and plasma TV. The hotel has an outdoor heated pool and breakfast is included. The Claim Jumper restaurant (great food, reasonable prices) is 50 yards from the hotel; Joe's Crab Shack is just beyond.
The Phoenix airport is 6 miles away, but part of the great price is that there is no hotel shuttle. They found that most guests have cars or a ride.