“I would happily send my kid to a school that had larger classes, no air conditioning, no science lab, no gym, etc. – if it existed.”
Bais Mikroh Elementary in Monsey has a very high quality curriculum and standards, however they manage to cut back on costs by implementing some of the things you mentioned. (from your list the only one they have is A/C.) This should be your first choice if you live in monsey. Being a Bais Mikroh alumni and Parent, I can assure you that in no way are the kids missing out by lacking an indoor gym or a high tech science lab.