Is it safe to switch front tires from left to right (or vice versa) by taking each off its rim and installing on the other? The intention is to retain the direction of tire rotation while switching tire positions.
Yes, you can do that without issue.
There are some concerns about rotating tires.
As far as the rotation goes, it is highly suggested you keep tires going in the same direction, not for safety concerns, but rather for longevity. When you run the tires in the opposite directly of how it was before, you run the risk of slipping belts as well as causing excess wear. This is the major concern.
Some tires do have a rotation specified. These types of tires, which are usually for performance/sport cars, will have markings on them. With these tires it is very important you keep them going in the correct direction or you may run into safety issues. These usually have directional tread which forces water out from under the tire through a pumping action. If ran backwards, it could force the water in towards the center which would easily cause hydroplaning even in the lightest rain. It is doubtful your Sport Trac has directional tires.
Ensure these tires are not asymmetrical, meaning, there is an outside and an inside to the tire. If so, you should not do as your suggesting. It is doubtful your Sport Trac has asymmetrical tires.