For what you’re asking, it’s been about 5 years for me too, but I can’t imagine it’s changed much aside from the NG sim and higher price tag. I went to Denver and as a mil guy too I thought it was cool floating around the United training center and seeing a 121 training world.
The toughest part was having the ability to study at home beforehand to show up prepared (systems, call outs, memory items, checked limitations, etc.). I took a couple weeks of leave beforehand so I could focus. Day 1 is the academic day, which is really kind of a check to make sure you understood things correctly and to fill in any blanks, not to teach things for the first time. Then it’s a sim per day just about, with lengthy briefs and debriefs. For those they give you what to study each day to show up prepared. I was more than satisfied with the level of instruction...all the guys were former United captains/sim instructors and were easy to talk to. I think the last 2-3 sims were all the checkride profile, so by the time you get to the checkride it feels very rote.
With all that being said I was partnered with a guy who may have been the most ill-prepared person to learn to fly a jet in the history of jets. I was sure there was no way he’d pass a checkride. He ended up getting un-paired about halfway through, got I think 3 extra sims and a ton of extra brief/debrief time, and he texted a few days after to say he passed. So they definitely went the extra mile for him.
Hope that helps answer the question you came here for, good luck.