Francisco, I got a full package booking all the camps from a tour operator, named Premier Tours (Goggleable?) in the US, based in Philadelphia (where I live), whose owner is a South African. Alternatively, you could book directly with Wilderness Safaris which is also easy to find on the Internet - makes sense from Europe.
You fly to each camp spending 3 or more nights at each to maximize your chance of seeing different herds of animals (You are flying 3,000 feet up over treetops and the views are spectacular). All animals are migratory and cover distances of as much as 50 miles a day. The animals don't stay in one place so you can't either. You will see thousands of animals up close and appreciate them in a way you never dreamed of. These small camps might have 6 to 12 raised platform tents and have all the comforts of home and more, e.g. some even have small swimming pools! Oh, except you probably don't have monkeys jumping up and down on your roof and elephants picking fruit off your raised deck at home.... These camps are 100s of miles from anywhere. You go out in the mornings and at dusk when it's not so hot. You do bounce around in the jeep a bit, so two weeks or so is a good amount of time. Food is really good.
The best tour operators in Botswana are targeting sustainable ecotourism and supporting the local population with guide and other jobs to discourage hunting / poaching. Here's a pic below of me trying to learn basket weaving from the locals - LOL.
If you have 3 weeks, a great trip might combine Botswana with South Africa. You could see Cape Town, the Cape of Good Hope, and tour the nearby wine country (Napa, Calfornia scenery pales in comparison although the wines are better).
Interesting story. Our bush pilot flew us into the Zimbabwe airport, chatted up their customs friends, and we were through in less than 10 minutes. Some tourists had been waiting there for almost 2 hours and were making no progress. We got nasty looks from them and one angry lady accused us of bribing someone!