The boards of county commissioners of any counties to which this act applies, upon the acquisition of lands for park and recreational grounds or entering into agreement for the purchase thereof, are empowered to adopt a plan for the improvement of same, including a lake or lakes, recreational facilities, reforestation, roads and roadways, and such other improvements as may be conducive to the recreation, convenience and comfort of the public and prior to the adoption of such plan, may employ an engineer to prepare plans and specifications for such improvements and make estimates of the cost thereof.