I remember back in high school, hearing how some classmates filled up their metaphorical plate with activities. After a full day of school they'd have clubs, extra-curricular classes, sports, sometimes jobs. Just thinking about their lifestyles makes me anxious. I can understand wanting to set yourself/your kid up for success, but having a bit of down time can be just as crucial to developing one's self.

Personally, I enjoy a number of hobbies, but none of them are requirements. That's what makes them work for me. I like that I can pick up and put down the scarf I'm knitting when I feel like it. I like that I can paint if the fancy strikes me, but I'm under no obligation to complete it (and every bit of practice helps.) Every so often I'll complete something, and that definitely feels good. But keeping them in the realm of "optional" goes far toward letting me create without feeling pressure about it.

As to low-demand lifestyles, I think a lot of people here have already said some great ideas. For me, I dedicate a lot of time to myself. I feel most demands from other people, but when I'm alone I can breathe. Yeah, my apartment's not sparkling clean. Yeah, some days off I won't shower. Maybe I'm late to take the trash out, or I tolerate some light hunger because I can't be arsed to cook something yet. I eventually get around to these things, I just do so in my own time. Executive function difficulties can be as much a spectrum as autism itself, though, so your mileage may vary.

If something's really important, I'll set up multiple alarms (as others have stated.) I have to repeatedly be reminded when I have obligations some days, lest I slip into the timeless void and realize too late that, oh snap, the bank (or whatever) is closed. I also have an aversion to alarm sounds, yet that helps me too - I'm more likely to remember to do a thing just because I want to avoid having to hear my alarm.