This will probably start the S... flying, but 8" logs = R-8, which is better than a tent, but way worse than R-19.
I'll have to admit that when I was younger, the idea of my own small LOG cabin in the woods was VERY attractive...... however, with the input of an Architect buddy, I decided to go with well insulated frame design.
One of the biggest problems with log construction is the eventual air infiltration from the logs shrinking & twisting- look at older log cabins, particularly arround the doors & windows at the settling. My uncle wanted a traditional log cabin, but used the newer T&G milled logs to be tighter- he also wanted a fireplace instead of a wood stove. After 20 years that place is so cold in the winter & so hot in the summer, I can't imagine someone living there full time. On the other hand, my cabin a few hundred yards away, takes but a few very small pieces of wood in the stove in the AM to keep the place warm most of the day- or in summer close the windows in the AM & it will stay nice & cool for the day.
I built my 24X32 cabin 10 years ago all by myself at the cost of $19,800 furnished. If I would have hired the work done, it would have been $40-50K. I suspect that if I was to build it today, it would cast about $50K in materials.
For the record, the water comes from a small stream a couple hundred yards away (could put hydro on it- have an old 1.5 KW Wind Jenny that I could adapt). That water is so pure & great tasting, that I could bottle it & sell it for twice what the best bottled water is going for in the stores! (yeah, I know- it should be boiled etc.- I wonder if the old Prospectors & settlers up there did that..). I have so much wood around, that it could supply a dozen cabins like mine.
In 1900 the old guy that originally homesteaded here, planted potatoes & a dozen apple trees (still bearing) & sold them to the gold prospectors (yes, you can still pan gold ot of the river- lot of hard work though!).
I'm just saying that if you are going to put your life & soul into a project like this, just don't get too wrapped up in the dream.... keep an open mind to what will be the most efficient for you in the long run. I did use half log siding on the outside- so that it does LOOK like a log cabin