Under-slab supply line?

I am running supply lines of pex from a utility room to the kitchen. It is nearly 50' If I follow the path of the drain line, the trench is open still for inspection on Mon. I am debating weather I should insulate the hot water line or not, and if so, what is the proper way to do it? It is under a heated slab in southern Mi, so the soil should be around 60 degrees.

My plan was to insulate with standard pipe insulation, and then stuff that in electrical conduit. I would run that in a straight shot from utility room to kitchen, maybe about 30-35 feet when not following the drain. I can not do that till after I fill in the drain trench cause they cross and will cause many cave ins I fear. thanks