I know what you mean about the cost of multiple agistments. It's a killer. It took us a while but found a nice old farmer who didn't want to sell his land and is now too old to maintain his property so we came to a deal.
We do the fencing which was already in reasonable condition, and maintain the shedding he pays for materials and we do the labour. All for the cost of paying agistment for one horse, even though we had three.
It works out well for us and for him. His family is happy as we keep an eye on him throughout the week when they are busy at work. If he's not able to get himself to the doctors/shopping/bowling we take him. I go up in the mornings and dh evenings so its not a huge deal. and he keeps an eye on the water for us and lets us know if he spots anything wrong with the horses so I think it works out for all.
We'll miss him when his time comes for his next big adventure or we find a property which ever comes first.

He has become a big part of our family. It's nice to have an adopted great granddad for the kids.