I thought the entire bench was available for the railroad. What you could do which would not add too much height to the layout at all along the line of Andrew's suggestion is to cut a piece of luan door skin material to fit the existing bench. Now cut off however much you need to remove to make space for electrical panel access. That becomes a removeable section that would connect to the permanent part via joiner tracks and some sort of small electrical plug in for track power. In the event someone needs access to the electrical panel, just unplug that section, and remove it. You might put a small shelf under the bench as a place to store that portable section when it is taken out so that it isn't damaged. Maybe even better than a shelf would be uprights spaced to mount 2 cleats so that the section could just be slid in place like a drawer. That way you don't have a shelf to store things on when it needs to be open for that layout section. The rest of the luan can be laminated to the top of the bench, or if you want it removeable for some unseen future reason, a drywall screw in each corner would fasten it down and be easily covered with a bit of plaster and scenicked. If you need to remove the screws, break out the plaster over them, and unscrew, the top then comes off for a move or whatever. If you centered the screw holes one inch in from the corner in each direction at each corner, a ruler would make easy location of the screws after scenery materials were hiding the screw heads. By the way, I would reccommend using an inch or so of foam laminated to the luan if it is to be removeable, a long piece of unreinforced luan will flex enough to put cracks in plaster type scenery materials.
Now to locat the wye. The wye would be centered just about where you wrote "36 inch door" on your drawing. You show a left hand turnout at the end of your oval. I would reccomend a #6 turnout with the curve being part of the curve in the oval and the straight would be one corner of the wye. Your plan show a right turnout leading into a second left turnout facing the other way for your branch line (red line). In my plan, that turnout would be the start of a branch line gradually climbing a hill that goeas around the central backdrop going to your logging camp and coal tipple. By the way, if the plan is getting too busy at that point, the logging camp could be made into a sawmill in a high plateau, and eliminate the log cars completely. Show a dirt road in the background with trucks bringing in logs, and the train hauls out lumber. Now off this "rabbit trail" and back to the subject. The crossing is eliminated; and in it's place you install a "Y" switch. That is a turn out where both directions lead into a curve there is no straight. The right side of the "Y" switch will be a part of the oval mainline, and the left side will be the second coirner of the wye. You will need to use broad radius curves to have reliable backing of full length passenger cars, so making a curve of appropriate radius, you put in the third turnout for the wye where the track from the end of the oval and the track from the wye switch meet. By the way, "Y" switches are very compact, but if I remember correctly the radius through them is broad so backing full length passenger cars through one should not be a problem.