These isolated/landlocked parcels are an expected outcome from the laws that created this property ownership situation. Going back to 1785, it was passed by Congress that newly admitted states would receive Section 16 of every Township for funding of education. That left Section 16 surrounded by other lands that were not State-owned lands. As time passed the amount granted to states was increased. For example, here in Montana, Section 16 and 36 of every Township was granted to the state. That is 2 of every 36 sections in a Township, or 5.6% of all lands would be landlocked as a result of this system. Some of the more arid states got even more than 2 of 36 Sections. That is the history of the isolated state lands.
On the Federal side, there is a similar history that resulted in this strange array of land ownership. The Homestead Acts, The General Mining Act of 1872, and the Railroad Land Grants from 1850-1872, where railroads were given every other Section in a 20-mile or 50-mile swath, for each mile of railroad built. Look at the land ownership along Interstate 80 in southern Wyoming. That is a classic checkerboard stemming from these railroad land grants. Similar incentives were provided to timber and mining companies.
The homesteaders were allowed to stake claims based on the rules of the Homestead Acts and subsequent amendments. Those were usually the most watered and productive lands. That left the arid or unproductive lands unclaimed, retained by the US Government or retuned by homesteaders who couldn't make a go of it on these poorly suited lands. End result is that these less productive lands that were in the hands of the US Government were surrounded by the more productive lands that had homesteaders making claim to. And, the original roads were built to connect homesteaders to the cities/towns, resulting in roads that were mostly over/across private lands, further isolating these public lands.
These events were happening 100-200 years ago, with lands having changed hands many times over that period, and with each subsequent owner paying significant prices (relative to the era) for these lands. Some current owners might use this strange ownership pattern for their own benefit, but they have the right to do that, given part of what they paid for when they purchase the property was the right to control access across their lands, whether to public or other private lands.
Any thought that the Congress or a State is going to somehow impair the value of those lands, via initiative or Legislative/Congressional action or a large scale Eminent Domain claim, is dead on arrival. Such would be a clear violation of the property rights granted these landowners via the 5th Amendment. If you believe in the tenets of the US Constitution, as I do, it is hard to support something that would be such a clear violation of property rights under the 5th Amendment.
As much as I want to see access to all public lands, my perspective is that we are best served to find ways to accomplish such and not infringe on the 5th Amendment rights of the landowners who own lands that control access to the public lands. It is not like a State or Federal agency did this by design. It is not like the original homesteaders or companies receiving the land grants did it to block access to recreationists in the 21st Century.
I would offer that hunters are far better served by supporting full funding of programs like the Land and Water Conservation Fund, increasing support for access easements, working on land exchanges, and the purchase of perpetual easements with willing landowners. It might not solve the problems as quickly as hunters of today would like, but if a long-standing effort was supported, over the course of the next 100 years, a lot of access could be obtained through willing buyer-willing selling agreements.