You can opt for Landowne in Uttarakhand according to the conditions you have mentioned. Travelling via flights to and fro Delhi and then taking a private car, you can have an excellent holiday to beat the summer.
Depends on where are you from? I live in Kolkata, I would suggest Sikkim for that. If in Delhi. Try Rishikesh or Manali.
Bangalore- Try Coorg
Mumbai- Try Matheran