Most guides in Botswana are associated with tour operators, based at lodges in the Okavango, Linyanti and Chobe. A few are freelance as for example, Roger Hawker in Maun e-mail email@example.com and Richard Randall in Maun e-mail firstname.lastname@example.org.
There are international flights direct to Gabarone from Europe but Lonely Planet suggests that it may be cheaper to fly to adjacent countries and travel overland to Botswana. There are buses as well as flights from Johannesburg to Botswana. Flights are scheduled regularly between Botswana's four major cities, but fares are expensive. Botswana has six major bus routes and a good train line running through Francistown, Gaborone and Lobatse with a service that's reliable and inexpensive.
Safety issues encountered in Botswana are no different from those met in many other African countries. Guidebooks, travel companies and the above websites provide much of the advice one needs, but some key points warrant repetition here. (1) be aware of the risk of malaria, seek current advice, sleep in a sealed tent or under a net and take prophylaxis as recommended. (2) always ensure you have sufficient water and some method of purification (even if this comprises a pot and a campfire for boiling). (3) do not under-estimate the danger of being in the sun too long. Ensure you use sun-block and drink plenty of water, and wear a hat. (4) Botswana has perhaps the highest incidence of AIDS in the world. (5) Ensure that you take a reasonably-equipped first-aid pack with you including a supply of hypodermic needles.