Good advice there as the box shouldn't get loose all of a sudden. Having the front wheels off the ground using jack stands under the lower A arms allows you to judge the feel of the box better around the straight ahead position and also allows you to check for rough spots elsewhere as you turn the wheel. It should be just a little bit stiffer when at the centre position. You'll just have to make a judgement on that. Adjusting to get 1" free play is optimistic in my opinion, I'd say that was too tight. 2-3" would be closer I think and even that is hardly noticeable when driving. Your alignment was probably only for tracking, toe in/out but the slack, where ever it is might be giving you a bit of toe out which makes the steering very fidgity. The shop should be able to find the problem if you can't, they may have left something loose. Sometimes tapers catch up and then are loose when they free up.
I hope it didn't spoil your trip too much. Looks as if you need to add it to your blog..................