If you end up having 5 adults and the little one, a 2BR at BCV (for example) in late August is 34 pts/night (drops to 32 pts/night Sep 1) for Sun-Thurs nights. For our trip last year and our upcoming May trip we did split stays, rented a ressie for Sun-Thurs nights at a
DVC, then stayed at POP Fri-Sat nights as those nights are about twice as expensive as weeknights.
If you were able to get a 2BR ressie for Sun-Thurs from a DVC owner charging you $12/pt for example, it would cost you $2040 (34 pts * 5 nights * $12), which works out to about $408/night. When you rent DVC you don't pay sales tax, so that $408 is like paying $362 + tax - a savings people don't always think about. Let's say with tax you rented 2 rooms at a value for $125 a piece, the DVC would be $158 more per night, but you can save quite a bit having at least one meal (if not more) a day in your room. Numbers obviously get better if you only have to pay $10-$11/pt, and it will rarely be cheaper to stay at DVC than Value, but you need to decide if paying a little extra is worth it.
For us, we're paying about $160/night for a studio, room-only at POP for the same dates was about $130-140/night (including tax), and for the extra $100 we felt it was worth staying at SSR over POP (but we do LOVE POP !)
My vote is for a split stay whether it's 3 or 6 of you making the trip, renting a ressie and then staying at a value. One thing that would change that is if free-dining or some other great promotion was being offered, so start scouting out the "codes" threads for you time frame.
Chris