Been at Kubu 1 July 2009. Been there in June and again middle May 2009, it was dry! Took my parents and in laws on a Bots trip end of June. Why would Kubu be a problem?
The swb Pajero my son drove cut out after 100m of water coming in from the north, we had a total of 8k's of water. You drive where the water is, because the road is more compacted there. Next to the water on the "dry" ground it was slush puppy. As you stand on foot you sink away, that's if the mozzies don't carry you away first or suck you dry.
Kubu itself is a wonderfull place and we enjoyed every moment of it.
Come next morning, we took the most western road that should be the driest. The Land Cruiser went ok, but the Pajero with less ground clearance got stuck often, and we also had lakes of water ahead. To cut it short, we slept that night after only 30km inside the vehicles, getting the Pajero through at 10 the night. Next morning only 5 km of water but more manageable.
When wet, you must be very patient, have the right recovery tools like sand ladders, spades and be at least 2 vehicles. Be ready to spend the night on the mud.
Will I do it again? YES.
Am itching to get there by bike, when it's dry. ;D