Thank you Annz. One of the installers called me back so he is the one I will use to install the floor. He is the middle of the price range and he told me he will take a break from the job he is on tomorrow to come by to let me know exactly what we need but from my description he feels I need 2 T-moldings (88" long and I need 4" more than this from my measurements for the two areas) and the reducer will not be good if the area is only a 1/8th difference. But he will see for sure and bring a floating pad and a 1/2" board. He also will let me know the exact number of reducers we will need since they are not returnable I just found out. He feels we have enough extra waste for the wood and he is very good at not wasting wood and is good at what he does. Hence, I guess I will wait for him to arrive tomorrow. Truehardwoods.com has been so patient with me and will give me a few more days (they have the order in the system but it is not yet sent to their distributor) to be sure about what I need as well as let me know which glue I ordered to allow me to change the wood glue to waterproof glue between the seams. Another installer just called me back and had no idea and that is not a good sign. So if the installer comes by tomorrow that called earlier, he has the job. I guess I better get back to my work and get a good night's sleep tonight and see what the installer has to stay that is stopping by tomorrow.

Depends on the age of the house. some older homes that rip out 1.5" planks and add 4 or 5" planks dont look right to me, but if it matches what your design is going for then who cares? unless your trying to fix it up to sell, in which case keep it consistant. Would you be feathering in the potential new wood to the old floor anywhere? a doorway? rooms meeting to a hallway? If not then go with whatever you feel like.

If you want vertical interior boards you will need to install continuous horizontal blocking between the studs, so that you have a nailing surface for each board. If you installed the interior boards horizontally you could nail to the vertical wall studs. You will have to compare prices, but the cheapest wood to use may be new pine 1X4 or 1X6 S2S, and then stained with a gray stain to get the look you want. Tongue and groove or butt joint is your preference. After installation there will likely be some seasonal shrinkage and movement creating some cracks between some boards. But it's a cabin, right? Good Luck!

Pallet wood is a bit too brutal for the installation, but the idea of wood look plank tile or laminate flooring seems like a good alternative. Thanks for the sources.