Welcome! What part of the Inland Northwest? I'm in Spokane. If you're anywhere near, I can get you connected to a couple of riding groups that welcome beginners.

Sounds like you're doing all the right things with the right attitude! Just keep it up and do what works for you. Enjoy the rides and don't worry about measuring up to anyone else. We're all at different places, at different times. 60-75 miles a week sounds pretty impressive to me.

Keep on ridin'!
(And when you're good and ready, we'll get you going on the mountain bike thing?!)