Having had 4 kids myself, Ex would not allow us to generally speaking use two rigs, so we went with a crew cab. If we would have had more, then it would have been a van. A burb was not an option no matter how one sliced it!
I would go with a 35 series 15 pass GM or a 12 pass Ford personally, with the biggest motor one can get in it! A V10 for the ferd, a 6.0 or 8.1 for the chebby. I would not recommend generally speaking, not that you will find too many chebby's, possibly ferds a diesel. Gas would be thebest bang for the buck cost to run etc for how you will use the van.
marty