There are some wonderful lines out there. I'm not experienced with most and can't tell you what is best for your fishing and casting.
All I can say is that I don't think you can go wrong in buying a Cortland peach 444, now called the classic. It is time tested and a great value for the money. May be better ones out there, but this is one that has no risk of disaapointing you as regards getting your money's worth.
I get the DTs. They work fine for me in the kinds of streams you are looking at and I like the idea of being able to turn them around on the reel when the first end gets worn out.
For backing, use Dacron. Any brand is fine. Most seem use 20#, but I use 30#. It fills up the reel faster and, fishing streams like the ones you mention, I have never seen my backing come off my reel.
Going beyond your initial question, I like RIO leaders and tippet. I can't tell you it is better; only that it works for me.
And that's the theme of this response. I'm not telling you what is best. I'm just telling you what works fine for me and gives me a feeling that I've gotten my money's worth. If I have problems using any of these, I don't blame it on them. I'm letting myself down with skills; the gear isn't failing me.