The plan is to put the unit on the back of the sled and yes read off a 2 line LCD.
The unit casing will be 3d printed so that everything is tight.
The acceleration would be used in a simple F=ma equation, the reason i mention the coefficient of friction is that is hitting the sled with the same force on different surface would give different acceleration readings as the friction force would be subtracted..... its needs to be accurate on different surfaces.