You can go with Flight from Zanzibar to Ruaha or Take boat From Zanzibar to Dar es Salaam
then flight to Ruaha (Iringa) it is more easy and you will have more time to spend in the park but more
cost.
Driving from Dar Es Salaam to Ruaha is 10 hours, with flight 1 and half hour .
You can also do 4 days 3 night.