Not all XCTF programs will have much of a budget for official visits. If not, you may be offered an unofficial visit that is very similar to an official one in length and experience, but you would be paying for the travel. Typically one of the days would be during the week so you child can go to class with one of the current team members. Sunday/Monday schedule was pretty common in our experience. There are often multiple recruits on visits at the same time.
As you might imagine, the fall will be very hectic with these visits plus fall xc schedule plus college applications plus regular schoolwork and extra curriculars. By the end of summer, we had seen enough schools on summer visits to really narrow down which schools to go focus on in the fall. Good luck!