By definition, an overnight is whatever you and a provider agree upon. I may involve 6-8 hours of continuous play, or several periods of hobby play and then other activities or rest/sleep.
Day-over sessions for 5-7 hours can also be fun--YMMV of course.
Suggestion for overnight:
First find a provider with whom you will be comfortable for multi-hour session, and them with you for same.
Next agree upon a hotel or other out-call location where you both will be comfortable.
Schedule a two-hour session from 10-12pm and ask if she would be available the next morning at 7am for a follow-up two-hour session.
Offer for her to stay over and not have to drive home and back for the second appointment early the next day.
Then respect the provider's time and make sure you both get a good night's sleep between the late night and early morning session the next day. If you are at a hotel with room service, breakfast in bed can be fun.
Make sure both parties agree in advance to planned times and duration of all hobby play, and be absolutely clear on expectations for general rest and non-hobby downtime/relaxation.
If more hobby time occurs spontaneously, then make sure to adjust the donation to reflect the additional hobby time/activities.
YMMV with ladies--some will flat out say: "No fucking way!" For things to work best, discuss this with your ATFs/LTFs with whom you know well and enjoy spending non-hobby time. I have done this multiple times at local hotels with great success. I have even had several providers ask when can we do this again.
Trips/cruises with providers can also be fun, but again, not on a first appointment with someone you don't know well. ATFs/LTFs whom you like and enjoy spending time will always work best.