Your idea to start a nursery school in New Vrindaban is very good proposal and you may immediately try for it by cooperatively consulting amongst yourselves how to do it. 
But one thing, we are teaching Bhakti by practical attendance and by decreasing playing desire or drive. If the children simply do as their elders are doing, that is, regularly attending mangal arati, rising early, chanting, eating prasadam, looking at books, worshiping the like that, then automatically they will become trained up in right way and there is no need for special program for education.
Children will always do as they see others doing, so if by the good association of their parents and the other older persons, they will come out nicely fixed in Krishna Consciousness, and because they are not spoiled by an artificial standard of sense gratification, they will think that performing austerities is great fun, just like in India we see the young brahmacaris are sent out to beg for their spiritual master to teach them humility and non-attachment, and they spend the whole day in the hot sun and come back at night, take a handful of rice, and sleep without blankets on the hard floor and they take this type of life as very much enjoyable and great fun.
This is how we train our children in Krishna Consciousness, just be keeping them 
always attending our regular program and associating with Krishna devotees, teaching them in spiritual realization by giving them the idea that sacrifice and tapasya for achieving the highest goal of life is a very nice way of life. Not that we shall give them many games for playing, these so-called scientific methods of learning are artificial, unnecessary, and on the whole I do not have much trust in this Montessori system or any other such system of teaching. Your idea for having altars to train the children in deity worship is very nice.
(Letter to: Satyabhama — Mayapur 28 February, 1972)
The simple method I have introduced, namely learn English and Sanskrit, is sufficient. Why the so-called Montessori method?
(Letter to: Satsvarupa — New York 11 April, 1973)
During Srila Prabhupada’s presence, when his Gurukula teachers began to seriously follow the teachings of Mary Montessori, Kirtanananda remarked, “They have taken a new guru.” That was the worst pronouncement and a sign that the Gurukula teachers had to immediately adjust their priorities and decide who was their Guru.
(SPN 2-49: Personal: Srila Prabhupada Demanded Loyalty)