I suppose it doesn't help that I'm usually with my kids or dog or someone's waiting for me, etc what I should do is get out by myself so I'm not rushed. Then I can adjust the settings slowly and figure out what I'm doing.
Speed comes with familiarity ... there's a LOT to understand, and it takes some getting used to all the buttons.
I'm trying to think of an example. OK, say I am in a field and I want to get some nice shots. I would probably use Av mode since I'm not too concerned about shutter speed unless it's low light, right? What if I want to adjust the ISO not with the back button, but using the arrow button? I find it difficult to know exactly what value on the EVF I'm looking for. And say I wanted to make the f-stop even lower than what it gave me. I can't easily change it. Just tried it again, in fact.
What mode to use has more to do with what effect you're going for than lighting condition.
You'd use Av mode if controlling the DOF is important; pics of flowers or stationary things. You'd use Tv mode if stopping motion was important; birds, animals or kids.
Use P when you don't really care and just want the "best pic quick."
The ONLY way to adjust the ISO that I know of is using the ISO button. The currently set ISO is always in the upper right(ish) side of the EVF.
Now, in P mode. Same thing. I can adjust the ISO pretty easily, but not the aperture.
Exactly. In P mode, the only things you can adjust are the things under FUNC (MyColors, White Balance etc) and ISO. The camera is picking your Av and Tv as it sees fit.
I see along the bottom there are numbers but manipulating those doesn't seem to change the aperture. I know that those numbers are relative to each other and I thought were aperture and shutter correlation. But if so, they're given in a different value and as I said, changing them doesn't seem to affect the aperture listed.
The numbers that appear when you half-press the shutter? Yes, they're shutter speed (on the left) and aperture (on the right). You can't change them in P mode (except by using the Exposure Compensation).
They are related, but not directly. Each one controls a different aspect of how the light is getting into your camera. Speeding up the shutter generally means you need to open up the aperture. But the shutter has far more effect over how much light gets into the camera than the aperture and it's got a more settings (called stops), too.
Sometimes I look at the EXIF data on my shots and I'm like

how did that happen, LOL.
So this seems to be where I'm having the problem. And it's not a huge problem, I AM learning.

But I'm not where I want to be yet. I appreciate input and I know what I really need to do is more studying and use of the camera. I hope by our late summer trip I'll know what I'm doing.
Please

if you're finding this as well, I'd love to feel I'm not alone here!
Thank you for everyone's help and support. We'll get there - together!!

I'm still learning, too ... I think even the pros are still learning!
The best way to do it is really to explore each mode (Tv and Av) one-at-a-time. It might help to think of Manual as simply Tv and Av at the same time! The camera is really a good teacher in itself.
Start with Tv and watch how the camera picks aperture values as you change the shutter speed from fast to slow. Notice how much of a difference there is, even in bright light, between a low shutter speed and a fast one. In bright sun, you might be shooting at 1/1000 or faster ... try that with some clouds overhead and you'll get a dark, dark pic.
Play around with Av mode and see what differences you get between the lowest and highest settings (remember that the further you zoom, the higher the bottom threshold is. At full zoom, I think, you can only get an Av or 3.5 ... at full wide-angle, it's 2.7)....
If you can't get a decent exposure with the shutter speed or aperture, it's time to start bumping up the ISO. It's the balance of the three settings that determine how your pic will look and there's really no better teacher than experience (one you understand what's actually happening).
ALWAYS half-press the shutter button in all of the creative modes to see what the camera "thinks" of your settings ... any setting that comes up red is a problem.