Visa (Nairobi)

Hello. I have just joined this forum as I am moving to Kakamega in September this year. It is all very exciting, the opportunity to volunteer for a wonderful charity, RUSH (Reaching Un-reached thro' Self Help) and to stay long term in the country I love most. However, I am getting a tad stressed about visas, I thought I could go out on a 6month visa and then extend, but I am being given conflicting information even from people at the Kenyan Embassy (who have been incredibly unhelpful!). Does anyone know what the best course of action would be? Also, I have booked a single ticket out there but been told I may be refused entry if I cannot show proof of return, is this true? Any advice, info or guidance would be so much appreciated as it is all looking very daunting right now. Thank you!