It is possible to combine climbing Mt. Kilimanjaro with a bike tour. Climbing packages for Mt. Kilimanjaro generally climb the Marangu Route, which is the most popular and non-technical. The elevation, not strength or stamina, is the challenge.
Most groups takes five days, four nights.
It is helpful to ask your guide at the beginning of the climb how many porters and cooks will be working with him. The porter carrying your equipment generally are not with you as you hike. Take multiple insulating layers of clothes, sturdy rain gear, alpine sunglasses, sunblock and sturdy hiking boots. Also a flashlight with five hours of life is very important for attempting the summit. You will make the final ascent in the coldest wee hours of the morning when the talus and snow is still frozen.