Another person posted a triplog for Finger Rock Guard here, so I'm going to take the liberty of doing the same. The route is essentially the same except for the very end - where the technical climbers go to the right and to the actual finger and the rest to the left and the guard.
This was a tough hike, our group of five experienced a 40% attrition rate before dipping down into the canyon to ascend up to the guard. I hiked Finger Rock Trial to Mt. Kimball the week before, and I found this hike to be more challenging.
The first few miles on the Finger Rock Trail before veering off east, toward The Finger are a relentless ascent. Not hard, but I find quite boring, especially on the way back (which can be full sun and slippery if you're hiking midmorning/afternoon).
Though I'm not a fan of losing elevation that I've just gained, the dip down into the canyon at the trail juncture was welcome. That same stretch on the way back, about 500 feet of relatively steep up, was also gratefully taken up by my tired legs. The steep, rocky, and dirty hike down from the guard was taxing for me. Every time my mind wandered or I glanced at the horizon, I would go into a controlled slide, if I was lucky, or fall onto something, if I wasn't.
As for the guard, I'm not a fan of heights. I made it to about 100 feet from the top when I chickened out. I probably could have made it and if I hike this again, I most certainly will. But I'll leave my pack at the base so that I don't have to worry about that throwing off my balance. There was only one spot that felt pretty exposed and I made it up (and more importantly down) that with little beyond a fluttering heart and scrapes and bruises for hugging the rocks too tightly.
I don't hike with poles, but someone in my group lent me one of his and I was SO happy to have it. The other person who made it the whole way with us, didn't have poles and seemed to do completely fine without them. But I highly recommend you bring at least one.
ETA: I think the mileage is off - as is indicated in the trail description. Unfortunately I don't have a GPS device so don't have the ability to calculate it. However, per description, it's about 3 miles before you hit the trail juncture and the unofficial (yet fairly well developed) trail to Finger Rock. Then I'd VERY roughly estimate a mile down into the canyon and then back up, up, and up to the Rock and Guard. Our trip leader posted the hike as 7.5 RT, but I'd guess 8+. We came back very slow, but I really can't imagine that this could be done in three hours unless you were running it (which would make you a crazy person), so the info on the trail description could be quite misleading to someone unfamiliar with the area.