Other than on the infrequent race day, pacers are worked slowly and calmly in their jog carts, not even the racing bikes. During off season many go back to their farms and when being brought back after a lay off, they are often walked and jogged on farm roads around corn or what ever is grown.
I knew some people in Michigan who used to take retired STBs and get them going for pleasure driving. They initially worked them at a fairgrounds on the small dirt track there. They kept it slow and relaxed and didn't have a problem. They introduced four wheeled carts as they went.
There are few naturally gaited pacers, so many of the pacers they took, simply jogged/trotted along without having hopples on.
I would be cautious, depending on the horse he may think he is sposed to be off at the races.
The Pacers are run here in Cali, along with trotters, (not in the same race) . I rode one years ago, and it would still on occasion pace, and that was hard to stay on ! Lol