http://www.mousesavers.com huge help with both of my trips, both taken in October. Stayed on property both times.
How Old are your children? You will definitely want to rent a double stroller while there, if they are smaller than say... age 8.
Stayed at
All-Star Sports in 2007, in the
Contemporary Resort, With a Park View Tower room, in 2010. Going in October saved us 40% on our room, both times.
1st trip was done on the cheap. We wanted the convenience of staying on property, along with the meal plan. We skimped where we could. For example: Upon reservation, we said we needed a mini-fridge because we had medicine we needed to keep cold. One was furnished at no charge. We kept milk and juice in there, and had cereal every morning. Drove the Hybrid for about $100 round trip, from Gulfport. Entire 7 day trip (Tickets/Room/meal plan) cost us less than 2k. You can stay off property, and plan your own meals, and save even more!
2nd trip, we splurged on the Contemporary Resort, but played things pretty tight the rest of the way. With the regular meal plan, you got 3 meals a day. You get 1 Snack, 1 Counter Service, and 1 Table Service. We used our Counter Service at Wolfgang Puck's Express (in Downtown Disney) every chance we could. Think Newk's style ordering/service, but with table service food.
TIP: As far as avoiding lines/crowds, go to each park when it opens, go back to your room around 11:00. Rest, swim, whatever. Go back around 5:00 p.m. and stay until closing. Peak times are in the mid day, and your kids won't be as cranky for being led around the park all day.
Considering staying off property, this year... Good Luck!