If you only have a week in Botswana, then base yourself out of Maun or Kasane and explore from there. From Kasane you can venture into the northern reaches of Chobe National Park for a few days, then book a boat cruise or fishing trip from one of the many operators in town. Victoria Falls is also only a short drive away, although it’ll probably be easier to join a tour group from Kasane than self-drive across the Zimbabwe border.
From Maun, a week is just about enough for a circular route through Moremi and the Savuti region, or you can continue on to Kasane if leaving your vehicle there is an option. Make sure you have at least two nights on the edge of the delta at Third Bridge campsite and/or Xakanaxa and at least two nights in Savuti.
Alternatively, take a counter-clockwise circuit south of Maun, west-east through the northern Central Kalahari, with a couple of days at the end in the Makgadikgadi or Nxai Pan National Park. This is not a game-rich route during the dry winter season – March, April and May are best.