I visited the ruins in July 2003. The site can be covered with a (mandatory guide, Spanish only) in about 45 minutes. It is located on the outskirts of the small town of Mamotambo, a 20 minute bus ride from La Paz Centro, which is accessible by frequent buses from Leon or Managua Ask to be let off at Las Ruinas and from there it's a ten minute walk down a dusty road to the ruins. Few facilities in the town or at the site. There had been fewer than ten visitors in the past three days according to the guest register. It is a very hot and humid location so bring water but it is well maintained. Especially interesting are the cathedral, a massive stone structure, given the overall size of the settlement and the governor's house, the layout of which is still the norm in nearby Leon. Plaster casts of the founders, one of whom killed the under, lie together under the cathedral vault. Monuments to the Spanish rulers and Indians who rose in revolt against them attest to the brutal, bloody history of the settlement. A final must is the climb to the top of the old fort for a stunning view of the nearby volcanoes and the lake.