We're a family with two young children(2 and 5 y.o.), currently living in the Netherlands. We are seriously considering moving to Spain. We wanted to move there, so we can finally start our own permaculture project/campsite. The idea is to get +5 ha of land where we can build our own passive house, and using permaculture for the landscape design, creating our own little paradise that we could also share with like minded people by making a small/quiet campsite on the same spot. We like to do things for the local community as well, maybe something for the local school, or maybe provide work during the season for locals doing for small jobs around the site. This August we are going to North Spain to visit some friends, but it would be great to meet other permies, that have done similar projects, and that like to share their experiences with us.
We will be back in Norther Spain with our caravan in August, on a project similar to what you are looking to create.
There are quite a few projects in the area, most private but all forming a small community of off-grid and permie follk.
We have not bought ourselves so I cant comment on that side of things but maybe knowing there are many others who share dreams of a similar nature (as we do).
Good luck in your search and maybe one day we may meet.