Cool. Just spent 2.5 hours into it, I liked it quite a bit.
It's definitely well thought out. I think most of the choices you made are on point.
As far as difficulty, well, I haven't died yet, so I'd see what it takes to include a few more faster zombies during the day. You'll note that <ahem> other people have died. =) Someone, and I won't say who (Doombringer101) found out that the Mechanic can one shot you. =)
http://guppycur.com/
Food is easy, especially with apples coming down and my propensity to chop trees. Perhaps every once in a while we get a poisoned apple, or one with a worm, and it makes us sick, but we can't tell the difference? I dunno. As it stands now, I can survive food/water wise, no problem off of apples, since they give both food and hydration.
The wilderness spawns are on point; there are quite a few zombies out there and it makes it harder to find time to do "other" things, but that's fantastic.
We're only day 4, and they'll probably be Day 9 by the time I get back on tomorrow, but we're taking notes and I'm recording, but overall I'm enjoying it.
The starting sheds are a fantastic idea, but we were wondering if you meant them to be invulnerable? If so, maybe put a 6 day timer on them or something?