Sounds like you've been researching and thinking things through in a good way. Many things you can't know until you get there and find out what it feels like for you and your family, and what your needs are.
Re: power, on-grid solar is ideal if that works out for you. Off-grid can be a challenge when the sun isn't shining.
We have a former outhouse that now houses a sawdust toilet and it works well. We followed the directions in Joe Jenkins' Humanure Handbook (www.humanurehandbook.com
) for composting and are very happy with the whole system.
Human urine is sanitary and safe to use in the garden and contains most of the minerals and elements found in commercial fertilizers. It's a great way to fertilize your garden and enrich soil, as long as you add plenty of water (3 to 10 parts water to urine). Check out the book "Liquid Gold" (www.liquidgoldbook.com
) for more specifics. My "Liquid Gold" sunflowers grew to 12' last summer!
Re: your other utility questions, I think you'll figure that out as you go along. It partly depends on the type of housing and utilities that are already available on the land you purchase, also on what you find is important by way of amenities as you go along. One word of caution--things that feel adventursome and even enjoyable on a camping trip may grow old over time (like doing dishes without hot running water). Do give yourself a break re: comfort and efficiency whereever the budget allows so that you don't burn out. And stop to smell all those flowers you and your daughter are going to grow! Wonderful idea... Flowers bring so much joy!
Best of luck, you're on all the right tracks,
Author of "YURTS: Living in the Round"www.yurtinfo.org
Yurtlady on Facebook