Section 12. The commissioner on behalf of the commonwealth may acquire by purchase, gift, eminent domain or otherwise such land, including rights-of-way and easements for the purpose of protecting or enhancing scenic beauty, as he may deem necessary to establish, protect and develop a trail across the commonwealth between the Connecticut and Vermont state line to be known as the Appalachian Trail, and he may provide shelters and other facilities thereon; provided, however, that the power of eminent domain shall not be utilized to acquire a strip of land bordering said trail no greater than two hundred feet in overall width. Any department or agency of the commonwealth or any political subdivision, district or authority may transfer to the department land or rights in land for said purposes on such terms and conditions as may be agreed upon, or may enter into an agreement with the commissioner providing for the establishment and protection of said trail. The Appalachian Trail shall be held, developed and administered under this chapter primarily as a footpath and the natural scenic beauty thereof shall be preserved insofar as is practicable; provided, however, that the commissioner may permit other uses of the trail and land acquired hereunder, by the owner of adjoining land or others, in such manner and at such seasons as will not substantially interfere with the primary use of the trail. Nothing in this section shall be construed to limit the right of the public to pass over existing public roads which may be or become part of the trail, nor prevent the department from performing such work as is necessary for the purpose of forest fire prevention and control, insect pest and disease control and the removal of damage caused by natural disaster. The commissioner may grant temporary or permanent rights-of-way across lands acquired under this section under such terms and conditions as he may deem advisable. The commissioner may enter into cooperative agreements with agencies of the federal government or with private organizations to provide for the maintenance of the trail. No person who has granted a right-of-way for said trail across his land, or his successor in title, shall be liable to any user of the trail for injuries suffered on said right-of-way unless the injuries are caused by his willful or wanton misconduct. Expenses authorized under this section, including the acquisition of land or easements therein, awards of damages, surveying and mapping, and the cost of development and construction, and expenses incidental thereto, may be paid out of funds heretofore or hereafter made available for the purposes of this chapter.