Do i have to raise the turntable (walthers 90') to the level of the track or do i put the turntable flush with the table top?Not sure and i want to do it the right way the first time
The approach tracks have to match the turntable bridge track as your engines/cars will not climb or descend a step. The track tops need to match within a few thousands so that things work smoothly when an engine moves onto or off of the turntable.
"Ideally", your pit lip should be nearly flush with the ground surface, but if that presents a height disparity of more than 1/64", you will have to adjust with a transition in the track (up or down), or raise the lip by placing blocking material (even string or wire would do) under the lip to get it up a bit.
Regardless of your solution, you can then use fill around the area to make it appear reasonably flush. Add a few bushes and shrubs, a few shacks and some old pickups, and stack some wheels nearby. You should be able to make it look quite convincing.