A whole lotta depends in the initial post.
Are any of the 5 willing to share a bed? Or sleep on the floor? Getting 5 beds on property won't be cheap, but if at least 2 are willing to share, you may be able to get away with two rooms at a value. Alternatively, possibly look into renting DVC points and getting a 2 bdrm villa.
Quick comparison of Jan 21-28 2013
5x$85 + 2x$99 = $623 + tax per room at All Stars. So 2 rooms would be $1246 before tax, something like $1400 w/tax. If the 5th person is an adult, add an extra $15 per night, or $105, totalling $1505.
Value 2 bdrm AKL villa is 185 points for a week, at the going rate of $13/pt via rental is $2,405. You may very well be able to find someone willing to rent for $11/pt, or $2,035.
The villa would give you 2 beds and 2 pull outs, (maybe 3 and 1) and at least 2 1/2 baths plus kitchen. The two value rooms gives you 4 beds, and 2 baths, with no kitchen. Not sure if you would be able to recoup the extra $550 through eating in room, as I'd figure on saving $8/person per day for breakfast, ~$300 over the week, more if you throw in some dinners or lunches.
Are you planning on packing really light? Fitting 5 people and 5 suitcases into most sedans would be a tight fit if you decided to stay off property and needed a rental, requiring 2 cars adds to the expense, especially if you add that 1 or 2 extra bodies.
Off site it will cost you $14 per day per car for parking, approx $25-40 per day for the rental, a few bucks for gas, figure an extra $300 easy over the span of a week. You very well may end up saving more than that if your offsite lodging has a kitchen so you could make breakfast, etc. One of the sites a PP mentioned would cost ~$100 per night for a 2 bedroom townhouse during the same time period. No idea if they have any pullouts, but you still would only have 2 beds. Assuming you can all fit in that 2 bdrm, $700 + $300 for car costs, you are at $1,000.
So some savings staying offsite, but other small things might add up. Now if you do happen to get a 25% discount at the value, which is within reason based off the last few years, the cost drops to $935, plus about $121 in tax, or $1056 for the 2 rooms, plus that extra $105 for the 5th adults, totalling $1161. Suddenly you are pretty close to the costs of the off property rental.
Alternatively, if you drop to 4 or go to 6/7, then free dining (if offered) may also make staying on property a bit more attractive. The $1500 for the two rooms would also then include 2 CS meals per person per day, which would be a big help to your budgeting.