Holy Cow! While doing some research for you I just realized that I was in fact using Endless Vacations - DUH!

I never realized it as I buy a "Resort Vacation Week Certificate" on skyauction dot com then I got to resortcerts dot com to book it (which I see, in their upper left corner, is run by Endless Vacations). (btw - skyauction is an auction site where you can bid on the RCI weekly vacation certificates and the certificates are good for quite a while but the inventory available varies). I have done this for every time we have stayed at Silver Lakes, so everything I told you should apply, but you can email them and ask and then you have printed proof that you don't have to attend a timeshare presentation, etc... I was very skeptical at first as we had attended one timeshare presentation in Williamsburg and it was awful - high pressure!

So I made sure I wasn't going to have to do this again - nothing is worth that.
All of that being said, we have been to Disney countless times, staying on and off property, and there is NOTHING better than staying on property for the full Disney immersion experience while NOTHING is worse than being with a family that is not happy and rested. I have done both and it may have a lot to do with the what you want out of your vacation and the personalities/temperaments of your children. I'm certainly not trying to sway your decision in either direction. I know it's a difficult choice!
I would love to help you weigh your options - give you our opinion of pros and cons to both if you want? Have you been to disney before, how long are you going to stay and what Disney resort do you have booked?
Thanks for letting me share what would otherwise be useless information.
Brigitte