Transitioning bikes

Your Trek can take a new fork with disc mounts, between that and a disc-capable wheel, you aren't out as much as a good new bike.
Either suspension or solid fork, depending on your preference...
Having settled on a new bike now, I decided to keep the Trek as a campground bike for when we take the travel trailer out, and to put on the trainer as an exercise bike. I hate to give it up, but I'm not sure I want to invest anything more for a new fork.

I have three Salsa bikes, the Woodsmoke, Warbird, and Cutthroat. The the Woodsmoke is a fantastic backcountry bike but is a little too upright for on road adventures (at least for me). Have you tried a bike with drop bars? You may be surprised. Both of my drop bar bikes excel at the tough stuff. The Cutthroat seems like a good fit for your needs.
The Salsa's seem to be quality bikes. Like many others, however, it's difficult to find a shop that has the entire line, in the right sizes to do a meaningful comparison.

I am not a fan of drop bars, as I am more comfortable at this stage of my life with a more upright position for this type of bike. The ECR kind of checked all the boxes for me, so that's where I am now. I may get used to the Jones bar, or maybe I'll eventually swap it out.

BTW, I am considering a job in the Denver area and may relocate. Where in Colorado are you? I have to think the riding out there is awesome.
I live north of Denver about 30 miles (La Salle). The best part of riding in Colorado is the diversity. 20 miles to the west of me has top notch mountain bike trails, I can ride from my house and get in endless miles of gravel, or I can ride from my office over lunch and get in some scenic front range views on rolling hills. There's a little something for all types of riders.
That sounds great; the job I'm looking at is in Broomfield. I'll be trying to find the right place to buy a house and get settled. I'm thinking by spring I should be ready to venture out.