My 3 cents;
I'd hop the fence and go after that deer, but before doing so I'd empty my magazine and put the bolt in my pocket.
If I were to encounter the landowner, I would first apologize for trespassing and then explain the situation (ie; I shot a nice buck X km's away, he ran onto your property, now I'm tryin' to find him, etc etc). Claybuster's suggestion to share some of the meat is a good one, I never would have thought of that, but it would definetely help grease the wheels so to speak

If the landowner is grumpy and asks me to leave, I'll leave without a fuss. I won't be happy about it and I'll probably kick myself for losing the animal, but by crossing over onto private property I
have made a reasonable effort to recover the animal, even if I wasn't successful.
If the situation degenerates further and the landowner calls the cops, then they can just go ahead and charge me with trespassing. I'll accept the consequences of my actions. Honestly, I'd rather be charged with trespassing than leave a wounded deer behind, because at least I was trespassing for the right reasons, trying to do the right thing. I'm not saying my morals supercede the law, but at least I can sleep at night knowing I did the right thing, even if it meant I had to break the law to do it (if that makes any sense).