I think if you are flying in WBC you might be able to acess the lounge when you land at DTW. The lounge at DTW is great for an US carriers lounge. Nothing like CX or SQ. They do have 2 showers. If you are able to find a fellow FTer who will be at DTW the same time they might let you in as a guest. If not, go for the one day pass. The airport at DTW is great for walking. Lots of different eats if you are hungry.