One has no more right to "travel freely" into or across improved land that one does not own [property rights] or for which one has not been granted a right-of-way, easement, or other such instrument [contract rights], any more than one has a right to "education" or "health care" or such. Whether the (improved) land in question is "public" or not is irrelevant. [1] Stated differently, one no more has a "natural right" to (the availability or use of) improved "public" land than one has a "natural right" to (the availability or use of) "public" schools.
It is no more a violation of one's rights to be barred from access to or use of improved but "publicly" owned land (or schools, etc.) than it is a violation of one's rights to be barred from access to or use of privately owned land (or schools, etc.) in the absence of any previously established contractual rights-of-way, easements, etc.
[1] Ideally, "public" (i.e. socially collectivized) land, schools, etc. would not exist at all. But they do - and their existence does not create or conjure up any "rights" that would not otherwise exist in their absence. Rights do not come into or go out of existence contingent upon whether something is "public" or not. Any notion that they do is pinko-commie nonsense (which is why "progressive" leftists are so enamored of "open borders").
