Neighbours can sometimes be jerks. Glad you'll stand your ground if they try to push things too much.
What are they doing to pus the boundaries right now?
You have to be careful. My family once had a property where we let neighbours drive through a part of it because it was the only way at the time for them to access their property by vehicle. But if you let people do that for a certain number of years it then becomes a public easement and then you can't stop people from driving on it even if you want to get rid of the access way and build on it etc. You'd be best to look up the law on such things.
Also, fences make good neighbours.
He's thinking of making an enclosure for his little doggie off of his deck. But off of his deck is my yard. So, that isn't going to happen without my agreeing to it. Not that I mind... but they have to ask nicely, since only a small section of that area is going to be their property. It's a very odd-shaped lot.
Plus, good advice... I'll be careful. We have a surveyor coming in to lay out the official property lines. I was going to do that anyway, since I have some plans to build near the edge of the property; this just makes it more immediate. If it comes to needing a fence, then a border-fence that Trump would be proud of will be going up!
Hopefully. I had a new neighbour who was sure we had some of his property. I told him I didn't think so but he hired a surveyor and it turned out half of his garden shed was on mine. I told him not to worry but he moved it anyway. It was never a source of friction between us and in retrospect, he did the right thing. In fairness to your new neighbour, it might just be a case of him not actually getting something he thought he paid for.
It is definitely a case of them not knowing. And a case of me not wanting to let them get away with their doggie sh!tting in my yard. That's why I'll just pay for a legal survey.
They seem like good people. I'm sure it'll be fine.