Entering upon the National Forests and other lands administered by the Forest Service and use of existing National Forest System roads and trails shall be permitted for all proper and lawful purposes subject to compliance with rules and regulations governing the lands and the roads or trails to be used. (25 Stat. 357, 26 Stat. 1103, 30 Stat. 35-36, 1233 38 Stat. 430, 46 Stat. 1421, 64 Stat. 82, 72