When a piece of property is landlocked, the owner is at a disadvantage because he has no legal right to get to the property. In order to get there, he must trespass on the land. In some cases, an owner may allow an adjacent property owner with road frontage to simply walk or drive to his land out of kindness, but if the owner with road frontage sells her property or moves, the new owners or renters may not be as kind. It is important to try and get a deeded easement to the landlocked property so that there are no neighbor disputes in the future.
Ask for an easement to be deeded to you. This is the simplest and easiest way to get one. All you need in this case is for an attorney to draft and record the easement and a land surveyor to measure it out.
Offer to purchase the easement. If the owner shows trepidation at the easement and is worried about who will be traversing it, offer an amount of money suitable to both of you that will reassure the owner that your serious about it.
Look for an old fire road or other road that is in disrepair. You may have to look for it on an old tax map or other property map. In some cases, an old road in disrepair is actually a legal right of way to a public road. If there is evidence, however, that a road exists or existed, you can usually make the case that the road was there and can still be traversed.
Try and have an easement of necessity by implied grant determined. This type of easement needs to be filed in the county clerk's office and if disputed, can be argued in front of a judge in district court. The easement needs to be proven by showing that the property does not have access to any public right-of-way; the property was at one time part of a larger piece of property that had access to a public road and that the property through which you intend to place the easement used to be a part of the landlocked property.
Consult a lawyer, and have him help you establish your easement through legal means. He will understand the legalities in your particular state and can help you file the correct papers if you are having trouble contacting your neighbors or getting them to consent to the easement.