Reporting back from my experience on Sunday at 6pm (prime connection time at DFW).

First off, the Terminal D lounges are a major hike from the C gates. If you are taking the train I would allocate 20-30 minutes minimum EACH WAY by the time you total up walking to train +train time + walk to lounge. Ergo, unless you are in Terminal D (or maybe 1 stop) I would not bother visiting Cap1, Amex, the Club etc. unless you have 90+ minutes before boarding.

Second, there was a line 30 people deep at Amex and a 30-minute waitlist at Cap1. No gracias, homie doesn't do lines.

Third, there is no Chase lounge yet (I guess I jumped the gun) instead the only option is The Club which takes priority pass. The Club is not particularly easy to find at least for us. While the Club was not as mediocre as the Escape lounges, the food offerings were super weak and seating was packed. Definitely not worth spending an hour in transit around the airport.

We tried walking back - the walk from the lounge to the D->C connector was not bad, but it left us at gate C-1 and we needed to be at gate C-35. Fortunately a golf cart dude gave us a lift through the C terminal. Again I would allocate 30 minutes for walking (no train) depending on your gate.

To top it off we ended up with a 1.5 hour rolling delay, which we could have spent in the lounge if our gate wasn't halfway around the airport. Not to complain, we got home at a reasonable hour...