It shall be the duty of said commission to prepare an inter-county highway plan for the participating counties and to designate thereon the proposed highways, their width, the counties through or into which they will run, and if these are existing highways, the additional right-of-way requirements therefor necessary to obtain the width desired. After such plan has been approved by the governing body of each incorporated city and village affected thereby, the commission shall record a copy thereof in the office of the register of deeds in each participating county. After the plan has been recorded as aforesaid, no plat of land in said district shall be accepted which is not in conformity with said plan. No structure shall be built on the land within the lines of any proposed highway except on a permit granted by said commission. The counties may in their contract provide rules and regulations governing the procedure of the said commission.