How will the family law court determine child custody and visitation if the husband and wife live 800 miles apart

I'm not a Colorado attorney but a quick perusal of the Colorado statutes seems to indicate that Colorado "joint custody" is very similar, if not identical, to Arizona's definition. Of course, you would need to contact a Colorado attorney to determine what the statutes have been interpreted to mean there.

In Arizona, "joint custody" has nothing to do with parenting time. I've seen parents in different countries share joint custody. The reason this is possible is because it relates only to decision making in major decisions related to HEALTH, EDUCATION and RELIGION. So, you would need to consult with the other parent when a major decision needs to be made in those areas and attempt to reach a joint decision.

Parenting time or visitation is completely separate and has nothing to do with custody.

The Court will consider where both parents live and may consider any other factors that are relevant to the best interests of the child, the standard for determining allocation of parental responsibilities(parenting time and decision-making). The Court can also consider why one parent relocated in determining if the relocation was in the child's best interest. Depending on the age of the child, the Court will order more parenting time if the child is older and may require the parent who relocated to pay travel expenses.