What activities are you looking for? I have found the website for Aso Farm Land (part of which is Aso Farm Village, hotel facilities), but cannot find the two others.
http://www.asofarmland.co.jp/top.htmlAso Farm Land seems to be a site including various types of spa - sauna, large baths, oxygen domes (!) - and some outdoor play areas, for the health-conscious. So if your kids as well as yourselves are interested in these facilities, it would be fine :)
But if you are looking for fruit picking experiences, Aso Farm land does not provide that.