I visited McChord a couple of years ago.The base has a freeway right down the West side.If you take an exit at the North end and proceed under the approach down the East side there is car park with a few shops etc on the left overlooking the base and approach.I parked in the car park and bought coffee and sat facing the base.The C 17s were very easy to get but the C 130s are quite a distance away and they are like the ones at the Hall and virtually impossible to read off.
Be warned, because you are next to a road with heavy traffic you may be reported by locals(which I was).
I then received a visit by Air Force Police and Homeland Security and had to explain myself.After proving that I was not taking pictures
and only serials they left me alone and I even returned the next day and read off the C 17s again.Best of luck on your trip.
