I haven't even read the entire report, and here I am commenting on the comments! It's kinda like participating in discussion in a literature class, pretending you actually read Don Quixote.
There are many variations on a high route from Cooper Spur to the A-Zone (upper reaches of Meadows). Not too much trouble, fun and scenic. Advance scouting recommended though, as there are a few tricky parts that might come as a surprise, and on "event day" you don't need that!
Sounds like your White River crossing needs some refinement, but I think you found the sensible exit point. I've exited much higher, and you can avoid the whole hassle by skirting Steel Cliff and popping out around Triangle Moraine, but that's flirting with "mountaineering", maybe not in the scope of your endeavor.
Getting to Reid from Illumination is easy on snow, treacherous without (just a few steps, but a crumbly unstable steep nightmare).
Yes, looping around behind Crater Rock and descending to the west is quite simple, but again, I've never done it without snow, and never hope to.
Recently, we discussed (in another topic) how to get from the Barrett/Pulpit gap to the other side of Coe. Since then, I've surveyed that terrain from high on the other side, and realize it's tricky. However, I have crossed Coe a bit above the terminus, where it's fairly well mantled. I can't recall if it's easy to ascend the moraine on the other side, or if I had to descend to the terminus (I remember I descended to the terminus, but I don't recall if it was because I wanted to, or because it was the only safe route). Anyway, from the terminus, or a bit below, I remember it was easy to stroll around, so I don't think it's necessary to get anywhere near the trail. I agree that it's pretty brushy just above trail, so if you're fighting brush you're too low. (This reminds me that I want to get back on Coe someday).
The drop from Cathedral Ridge to Ladd is absolutely doable, but you kinda have to be strategic. Pretty sure I failed once, but went back and did it right. Wait, am I thinking of Gladd ridge? Anyway, point is you can get from Cathedral to Barrett offtrail without too much trouble, but might require some backtracking if you make poor/unlucky decisions.
I'm flattered that Jerry thinks maybe I found a high route from Paradise to Yocum, but no, just to Illumination Ridge. Between Illuination and Yocum I've poked around a bit, but haven't linked it all up. I'm told it's a PITA, and everything I've seen suggests it is.
A possible way to avoid the Yocum Ridge trail: If you must use the the TLT to get from Paradise to Yocum Ridge, then at Yocum you might as well stay on TLT just a little longer, descending to Muddy, and follow it up to the Sandy Glacier. I'm not saying it'll be fun or easy, but that's not the point, amiright?
In conclusion, if I were crazy enough to attempt a true offtrail circum, my greatest anxiety would be Reid canyon (Paradise to Yocum). I'm moderately confident I could pull it off, but the question is, would it be a stupid bushwhack a hundred yards above the trail, or would it be a satisfying fun scenic segment? Above, there are links and more links, matryoshka topics referenced within topics. Ain't nobody got time for that.
Regarding trekking poles: I always break my tips. Heck, I should just cut a few inches off them when new, and epoxy plug the openings. I like a simple two-section camlock style, very little to go wrong. And if something does go amiss, the top section is long enough that it's not worthless.
Regarding pace/timing: You wrote "
Doing this route in 3 days was harder than when I did the 42-mile Timberline Trail in one day." Now that's interesting! Good to hear a comparison from somebody who has done both. Sometimes I get so discouraged at how slow I move (like my last hike where it took me 5 hours to do a little more than 3000' EG).
What a fun topic! I must tear myself away, before my evening disappears.