Before I head out on one of these 3-4 week trips, I try to cook a few dinners that will generate leftovers for the family. Roast beef is an easy one for that.
A 3.5-4 pound sirloin roast fits nicely in my dutch oven. The seasoning mix you see there isn't regularly Tony's, but a "spice n' herbs" blend for grilling/blackening. Its a bit less salty than the classic creole seasoning, and does well for a roast or a whole chicken. I brown the roast using the top broiler element in the oven for a few minutes top and bottom to let the seasoning kick in and do it's thing, then add some water, red wine, cover, and let it roast away at 375F.
A couple of hours later, and here's the finished product. The gravy sometimes needs a little thickening with a quick roux, then it's good to go.
My family was always a classic roast and mashed potatoes household, but Mrs. YatPundit grew up in a rice-and-gravy house, so we do things her way most of the time. Add some mushrooms I tossed in the pot with the roast and here's a great "comfort food" meal.