I think WBC is a good option. Still on property, but not really. They have buses (times they pickup are pretty far inbetween, but it's doable if you plan on being there all day). Last trip DD and her family stayed at ASMo and DS also was at ASMo. DH and I camped at FW in our camper and everyday we had everyone eating with us because the ASMo rooms are pretty much bare rooms---no nothing except a bed (and TV). This trip we are at WH and family decided to go to US. I would think for 8 days, there is going to be some time your family may just want to veg around the resort and from what I've read WBC has it all (mini golf, lazy river, heated pools, etc.) For our family we can't justify the Disney price any longer (and we were always onsite people). Check out this:
http://www.disboards.com/showthread.php?t=2114303
http://www.disboards.com/showthread.php?t=2114303
you can stay off site.

).
Good luck and only you know your family best and will know what you will cope with best 