1. I can get 7 4" brookies 5 minutes down the street. If I go 90 minutes to fish, I'm picking a place where 30-60 fish is more the norm, averaging more like 6 or 7", with a decent contingent closer to 9-10".
^^That's if it's a known stream. I like to explore new streams too, and they're a crap shoot, but discovery is a big part of the fun. As is the research to try to improve your odds.
2. Bamboo NEVER goes on brookie outings.
3. I don't carry backpacks. On the most ambitious outings, maybe a fanny so that I can carry a drink and snack. Usually, nothing beyond my Richardson and some tippet/shot in my waders pocket.
The fun is in where it takes you and the entire experience, not reeling in a few fish.
I also fish big water. Admittedly, I don't make it to true "rivers" like the D or the Lehigh very often, just not convenient enough to my locations. I'd enjoy them, though. Heck, I enjoy fishing the salt on the rare chance I get to. But I fairly frequently fish streams the size of Penns, Spring, BFC, etc. In fact, they'll be my primary focus from about March through May. I enjoy them. You'd enjoy a few brookie outings as well. We may, afterwards, retain our preferences, but variety is the spice of life.
As far as success, I'd expect you'd kick my arse on the true rivers. Especially if drift boats and double hauling weight are involved. I just don't have that much experience. On the medium streams that I do fish, I don't know where you rank, but I expect I could hold my own. As for the small streams, again, I don't know where you rank, and it depends on the difficulty level of the stream. But if you've truly never done anything like that, and faced with a thicker stream, I'd expect an experienced small stream guy who gives his full effort could at least double your score on your first outing. With an otherwise experienced background and decent ability to cast, though, after only a few outings and an equipment adjustment or two, you'd catch on and be able to narrow the gap. From there, your ability to fully close the gap would depend on whether you could maintain focus during a long day chasing "dinks".
I too have Simms Guide boots. I think this will be their 3rd season, so the jury is still out. They are showing considerable wear, but I can't say that I see any signs of catastrophic failure. Just a beat up surface appearance and flattening tread on the ball of my foot where I push off. I'll consider them worth their money if they survive 4 complete seasons. I'd give that a 50/50 at this point.