I offer the same type of service to my out of town clients. I usually charge a monthly fee equal to a individual client session, which covers weekly phone calls and emails, as well as answering any questions they may have throughout the month. Then a fee to create the workout(s) and progressions depending on what the client’s needs and wants. For some clients, they also want a demonstration of exercises, videos, nutritional review and body composition analysis. For those clients, I charge an additional fee for the month depending on the extent of their needs and wants.
In short, they get charged less than my individual clients get charged who are seeing me several times a week, but they are still charged my normal hourly fee depending on how long it takes me on average to meet their needs.
I hope that helps,