Nyamera:
I don't know about the areas you are interested in. In the past you have been far more daring than I in the places you have stayed, walking all over the country, etc.
However, on this trip I can only seriously caution you on two scores.
They are still having serious rain and flooding in many areas of the country with road washouts, etc. Many of the mud homes have collapsed. Please be sure you aren't driving on your own. Pay the extra for traveling more safely with a professional.
Also, there has been a spate of Mungiki killings lately - very barbaric with beheadings and leaving people's heads on fence posts etc. Though at this point no tourist has been targeted, things are heating up between the police and Mungiki and some innocent Kenyans have been killed in the cross-fire.
Thus your safety has to be primary before cost, accomodations, etc.
Go on www.Kenyalastminute.com (run by Southern Cross Safaris). You might find some deals there. If you see something you are interested in you can email them at sales@southerncrosssafaris.com (Phillip would probably be the one that responds) and request a price. They are an extremely reputable travel company and you would be safe with their drivers. You don't give us a price range to work with. My July trip for 18 days including airfare within Kenya, charter flights, etc is $5,700.00.
You may run into a problem with booking now. When I made my arrangements about three months ago many of the places I was interested in were already fully booked. I would defrinitely contact Phillip and let him know what you are looking for and an approximate price you are willing to pay and see what he can come up with.
Good luck - and keep in touch please.