I could possibly due a leg of transport if it was on the weekend (and by me, I mean Zach would probably be willing to take a drive to the DC area and tote along Uncle Fred).
Dr. Mom, none of your older children would be able to divide up weekly walking/exercising of the dogs? I don't know if you do dog parks, or jogging, or what, but you don't think it would be possible to take them for a run 2-3 times a week? I know doggy day care is really expensive, but even just getting some harder exercise a few times a week really helps most dogs.
Or your little ones, even (I don't know what ages your children are but I know they vary) can't do hide-and-seek games with the dogs and such to tire them out?