Okay, now I have seen all three parts of this and will try to convey my thoughts with minimal spoilers:
First off, the plays can certainly be seen out of order and it's not that necessary to see all three. They all take place in the same rundown NYC building, the first in 1953, the second in 2003, the last in 2053.
They're not exhausting: the first two parts are 90 minutes each, the third clocked in at more like 105 minutes today.
TDF tix are fine, because the seating is general admission. And they've reconfigured the theater so that there's only three long rows and a little over 50 seats in all, extremely intimate.
The good news is that the actors are ALL wonderful and a week in to performances, you'd never know that they'd only just gotten started...very polished.
Bad news is that Rapp's work is pretty uneven. He alludes to it all being a "glorious mess" in the playbill and yeah, he is right about the "mess" part...You get the feeling that he writes a LOT and doesn't edit himself too much, really enjoys taking chances, and doesn't agonize too much when he misses the mark.
AfterEight is correct that squeamish theatergoers might cringe a bit, but honestly, there wasn't any of it that I found troubling, although over the course of the three parts there were gunshots, bare butts, full frontal male nudity, some vomiting, plenty of blood, and some excretory stuff. But that's me
The first part, "Rose," worked pretty well, and the second part, "Paraffin," was my favorite; Rapp seems to be at his best when he's writing contemporary characters. The third part, "Nursing," takes a giant leap into futuristic sci-fi, Brave-New- World terrain with a story about a man who volunteers to be injected with horrendous diseases for the edification of museum goers and Logan Marshall-Green acts the hell out of that role...but by the end, Rapp has thrown in everything but the kitchen sink and I just hated the final moments of this trilogy.
I'd have to say that I didn't regret going...only wished that the third play had hit its mark. I worried going in that the premise would be a tough sell, but I think there were things he could have done differently with the last piece that might have helped it...and I'd much rather have ended my day of theater with Rapp on a higher note. But always interesting!