We are a family of 4 travelling with 10 & 11 yr old boys. We are planning a 3 week drive from MD to Yellowstone/Grand Tetons with the Black Hills & Roosevelt NP included. I am wondering if we should route our trip so that Yellowstone is towards the end. My concern is that after Yellowstone, Grand Tetons might seem anticlimatic. Is my concernunfounded?

The Grand Tetons are wonderful to look at. You may want to do a raft trip on the Snake River, late afternoon when the animals are feeding. I "like" Yellowstone and I suppose it is more exciting than GT. Try to include the Badlands in your trip. They and you will REALLY like/be impressed by that. Not sure where Roosevelt is. We stayed a week at a dude ranch in GT with young children. Trail rides, etc. It was great.

Hi mom2boys, hopefully you'll get lots of responses, but I'll throw in my 2 cents...We drove through the South entrance which goes through the tetons themselves, around Yellowstone and back out, and I still more impressed with the Tetons....unbelievably majestic...enjoy

The Grand Teton is indeed "unbelievably majestic." Whether youngsters will appreciate this splendor as much as the attractions in Yellowstone is questionable. I could certainly understand it if they found Yellowstone more exciting.
Still, there is much to see and do in the Teton, including the aforementioned float trip and animal viewing, along with some wonderful hiking.
I'd say to set your itinerary to do what's most convenient in your overall planning.

Either way you go will be fine. Each park has it's own special qualities.

At the Grand Tetons ask the rangers where to find moose at dusk. They usually know the best spots each year.

Utahtea

Utahtea - after you find a moose, what do you do with it?

We went to Grand Tetons before Yellowstone, and while they were beautiful, this area doesn't compare to Yellowstone... I was glad we kind of "built up" to the most beautiful spots rather than the other way around.
That said, I don't think the Tetons will be a big disappointment, either.
Don't forget North Yellowstone! The prettiest area of the park, IMHO.