I've been there in 2004 around april. During rainy season I was told the park isnt accessible.
Was very dry, and as of vegetation not much to see. Did see some animals, but it didnt compare to the parks I visited in South Africa.
The drive from Kaolack to Tambacounda was not very comfortable, very high temperatures, bad roads and a constant strong wind blowing sand
We stayed in Simenti. Prices were high, but what can be expected for some western accomodation in the middle of nowhere.
We had an aircon room, but the airco made so much noise, it was hard to get to sleep.
The temperature was higher then I've had experienced so far in Senegal, also much more humid. Everything you touched was warmer than you body temperature, not nice.
The food at Simenti wasnt very good, several guests got the runners... Stay clear from their non cooked foods. They pump their water straight from the river. Its bloody hot and I doubt it's filtered let alone cleaned.
We got mixed information about the existance of lions and elephants in the park. Have seen baboons, some deer, swines, hippos, crocs and all kinds of monkeys and tons of termite hills.