Your best option is to buy into Kidani. You would probably need about 125 points to go every other year and stay in a 1 bedroom Savannah view. We are a family of 5 and decided Kidani resale over Polynesian direct.
Since we have had our membership we have stayed at BRV (Studio), Kidani (1 Bedroom), and Boardwalk (Studio, only 4 this year). The one bedroom are so much nicer and give you room to spread out, which you will need as the kids get older.
We are looking to add on again but the current offering at CCV does not work with families of 5 without buying more points than we want. I am hoping the new Riviera has more options, or we may just try to buy some AKL direct since the current resale pricing is getting up there.