I didnt read any other posts so forgive me if this has been said but Id aim for a gelding if you want a nice clam trail buddy. We had an arab stud that we got from a woman who seriously never touched him and when they moved him from paddock to paddock they used a lungeline with a shank on it, and let him have as much of it as he wanted. Hed rear and spin and show off and they just let him. Then the abonded him and he was my problem. I never once had to put a shank over his nose, or give him tons of slack, but he did get very high strung around mares. I broke him as a stallion but there has to be no other horses in sight. This might be different with a younger guy that's socialized, but I would still shoot for a gelding instead. Even a year after we gelded our man he still thinks he's top dog. All 14.3hh of him ha ha
Arabians in and of themselves are one of the most spirited breeds there are, and having worked with and handled so many Arabs, and a few studs, they are certainly not the calmest there is! That's not to say they are mean, or so hystrung you can't handle them, but I would prefer to work with a QH stallion than an Arab, if I had to choose between the two.
I would recommend, especially, if you don't have prior experience with a stallion, that you keep looking; find another gelding, or a mare. Stallions, no matter how calm they are, should not be handled by those who are inexperienced in how to handle them, and certainly one who is not experienced in dealing with a stud should not own one, especially if they are going to be riding where they may encounter mares in heat; no matter how calm the stud, that can all go out the window if there is a mare in the vicinity.
I would not recommend a young stallion of any breed. We have a 5 year old QH stallion who is very well mannered, even when mares are in heat, but he has been worked with intensively since he was young to get him used to being around them. He only breeds in his field, and he is expected to act just like our geldings would anywhere else. He does get a little antsy about girls or other stallions, but my geldings do as well to a point. He has learned to stay calm, not squeal and kick or exhibit "himself." It makes for a nice ride, but on bad days he is strong so it takes a strong handler who he trusts and respects to work him in stressful situations since he is still in training.
I think with the right handling any breed of stallion can be a good riding companion, but you need to have experience with stallions or someone very experinced in training stallions to be like this. We have one gelding that is a gelding because he couldn't keep his mind straight. Ours keep their mind and their manhood, or they lose their manhood. We refuse to have a crazy mean stallion.