ok, questions...... when are you going? bc i dont believe, based on the information here......
http://www.wdwinfo.com/disney-dining-plan.htm ........ that the downtown disney restraunts arent included in 2010.
now if your going in 2009, it shows they are.... but, if thats the case, dont bother with the water parks imo. most of the stuff at the parks are closed for renovation and i think blizzard beach is actually closed totally right now. other thing is the weather right now in fl is WAY too choppy. it will be 80 one day, 60 the next, rain the next day, then in the low 60s again, then back to 80, then rain. its rediculous right now down here.
as for disney quest, your 9 and 7 year old would love it, but the 4 and 2 yr old are kinda iffy imo, the 2 yr old i would say def no (they do have height restrictions for alot of things still), but the 4 ........... idk. the good thing is that the movie theater is right beside it, and ifyou do go, then what i would suggest, is let the 2 go to disney quest with 1 of you then take the other 2 to the movies.
NOW, if you are going in 2010, and the water parks are in full swing, i would go to the water park in the morning and then do disney quest at night. that way the younger ones will probably be tired enough (because the water parks will BEAT YOU DOWN physically if your there for a long time) to pass out, dad or mom can take the older ones to game out, and the other can sit back, relax and have a coctail! (i suggest the mom to be the one to stay, not just because dads usually love games too, but moms deserve a little quiet time with no screaming or kids running around).
if you feel like taking them all, and the little ones get annoyed, you can always take them out and walk around down town disney (and as far as strollers, try to bring an umbrella bc the parking at DQ is limited to outside and rith inside the door which isnt much). its alot more family friendly at night espically since pleasure island (the bar scene) is no longer there. its not a far walk from one side to the other, and we actually will someties leave a park early to just go walk around bc its a nice atmosphere.