Hey Arliss, if you have a few moments check out my greenhouse build, maybe it'll give you some ideas on your build.
https://permies.com/t/231688/PAHS-High-Tunnel-Batch-Box
I'm in Kenai, so I know what you are up against when I comes to the lack of sunlight haha!
Have you dug into the ground on your property? I got lucky with mine and discovered that it was pure sand once I got past the eighteen inches of clay. I utilized the sand as a large thermal battery for keeping my high tunnel warm longer than your typical Alaskan high tunnel. Also, by only growing cold hardy crops in the beginning, I was able to plant seeds March 26th, and I was cropping mid May. I'm pretty sure that I could have planted sooner, but I was building the masonry raised bed in March.