So, what is the verdict on the gas - higher grades have less or no ethanol?
Don't know where you are, but you said it snows and you are moving to Pit. perhaps you are in PA. I live in Florida and we don't have that worry.
We do have ethanol in the gas and they use the same percentage in all grades ... at least they say they do ... perhaps your state is the same.
We have a 1973 1 ton dual flatbed with a 300 and 4 spd manual (1st gear is a granny) that sits for EXTENDED periods (this last time for about 3 years) and we didn't really do anything with it. It still cranked, but the battery was dead and needed replacing. There is also some rust (well, there are some areas without rust would be more accurate) on the cab - wood flatbed.
I would recommend doing much more than we did

since you have a much nicer truck. Ours sitting that long was actually unintentional, but good to know how durable the truck is.
As far as a cat goes ... as long as she has somewhere to get in out of the weather and a place to get water, she will feed herself - ours do. If you feed them too much, they won't hunt. Just take some cat food when you go and give her some when you are there to supplement her natural diet.
If you store any animal food at the camp (cat, dog, cattle, horse, etc.) keep it in a trash can with a tight fitting lid to keep the local critters from finding it and helping themselves.