Re: I Use a Path to Get to My Dock That Crosses My Neighbors Property, Can He Fence I
It's not likely that you could ever claim the portion of his property covered by the path as yours, but it is possible that it could ripen into a prescriptive easement. Your neighbor can prevent that from happening either by preventing you from using the path by building a fence, or he can grant you revocable permission to use the path to access your dock.
The best solution, assuming that your dock is on your property and that the configuration and terrain allow for it, is to access your dock by creating a new path wholly on your property. The next best solution is to get your neighbor to agree to grant you that revocable permission. He may not believe you regarding the fact that permissive use blocks any adverse claims which have not yet ripened, so suggest he verify it with an attorney.
Also put yourself in his position. He has heard just a smidgen about Adverse Possession (sometimes called squatter's rights), and so knows that there is a way he can lose ownership or rights to his land if he lets others use it. Would you take your neighbor's word about permissive use as a block to such adverse claims? Would you be inclined to pay an attorney to verify it for your neighbor's benefit (so your neighbor can continue to use the path)? What is the benefit to you that a fence won't fix?
To answer those concerns, are you willing to 1) potentially reimburse your neighbor for that consultation with an attorney (might be up to about $500); 2) agree to limited use of the path; 3) agree to pay some amount for continued use of the path? If you can't or won't answer 'yes' to each, start relocating the path onto your land. If you do relocate the path onto your own land, you might be able to talk the neighbor into not building a fence and so keep your view intact.
Good luck. I hope it turns out to work well for both you and your neighbor.
I'm a surveyor, not your surveyor & not an attorney.
Advice is general survey, not legal. Hire a local professional for specific advice.