That sounds low to me. A hotel room is going to cost $50 - $100/night even if all of you share one room. Campgrounds are not free, even if they are National Park or local Park campgrounds and commercial ones approach motel prices.
Unless you are buying all of your food at grocery stores and sharing the cost, restaurant meals will cost that much and more a day and you will eat a LOT.
One more thing, your van will struggle to get 20mpg and 60 miles/day is at least three gallons of gas or $12 at today's prices.
For two or more people traveling together, I'd allot an absolute minimum of $50/day and don't be surprised if you spend more.
As an example, on week long supported organized rides (like GOBA, RAGBRAI, etc.) where all of the transportation, "lodging", etc. is taken care of in advance, I find I spend about $30-$35/day just for food and I don't eat in lavish restaurants either.
This message was edited by DaveB on 7-25-08 @ 6:44 PM