Im looking at taking our horses out this year as well. More to pack the kids around with me than anything. If you haven't looked at the haflinger horses then I recommend that you do. Very hardy horses, good temperament and easy keepers. Used by the Swiss army in the mountains. Surefooted and can survive on whatever they forage. I half rationed our little haffy last winter and he put on weight eating down shrubs and small trees along the creek. Easy to break as well if you buy unbroke.
We will see how our trip goes this fall with the kids (6 and 3). Im hoping they just enjoy riding around "looking"for animals.