It's funny that you bumped this, since I just got finished playing an off the grid sim. I do not have Eco Living so there is no power generation. I could gather water, but there is no way to generate power.
There were a lot of annoying negative moodlets you have to deal with, especially early on. Washing dishes or your hands or taking a shower often gave a negative moodlet. The weird one is that sometimes you get a "Nature's Revenge" moodlet for eating a harvestable. For me, it was usually eating one of the emotion berries so the positive moodlet overrode the negative one. But it acts like food poisoning, so unless you have steel bladder, it can be a problem.
Cooking was a problem because my sim was a foodie. The BBQ drum never gave me anything but normal food, even when I had the grill master reward. It got better when Father Winter gave me a really nice grill. You can use the wood stove, but there are only 6 things you can cook on it OTG. And it's all stuff you can cook on a grill anyway. I had to have his birthday party at another location because there was no way I could bake a cake. I guess cakes and pies were a mid 20th century invention
Refrigeration is bugged. There is the icebox that works perfectly fine. You do have to add ice to it and it seems to last about a day. I had made some Foragers Stew early on and it stayed fresh even when I forgot to add ice. But one time I made some Breakfast Scramble and forgot to add ice. It spoiled while the stew stayed just fine. Sometimes it seems like the timer on the spoilage for food just goes away. I don't know why. Ice doesn't cost anything so just add it when you think of it.
Lighting is fine. Most of it is kind of dim and yellowy. There is really only one overhead light and no wall lighting. A lot of the table lights are candles which look cool, but take up a lot of space. My favorite light was the No Fear Night Lantern from Outdoor Retreat because it was the brightest light.
There is some other weirdness that makes you shake your head. There is no OTG radio, so during the Kava party I had no way of getting people to dance. You can plan a vacation using your phone, but you can't buy a lottery ticket. I bought sprinklers for my garden and they worked at first, but after 6 AM the option to turn them on was grayed out. The reward sink that I got from the Culinary career worked just fine even though it shouldn't.
All in all, it wasn't that bad. Just annoying at times. But it was on Sulani, so I imagine it would be problematic living almost anywhere else. Sims tend to get miserable if you can't heat your house. I'm not inclined to do it again. It would be neat as an idea for a vacation home. But everyday life was just unnecessarily annoying.