When the State Highway Commission has completed its investigations with respect to any proposed national parkway development, it shall make its findings and determination with respect to such proposed development. Such finding and determination shall state whether or not such proposed national parkway development is deemed advantageous to the state, shall include such information with respect to the development as shall be necessary to state its character and extent, and shall estimate the cost thereof and separately, the amount and character of lands necessary to be acquired in fee simple and in easements, with their cost, and needed to carry out the development.