I agree with leaving the GPS off . By all means have it nearby as an "aid to navigation"
In my GA days one was very lucky if you had an ADF.
Fly by the clock and the compass and map read using the 1 in 60 rule.
You will get more satisfaction and much more experience out of the trip.
A better pilot will always have a good grasp of all the basics in any area of aviation.
Emeritus.