For me, one of the main attractions of that layout is the fact that there is very little straight track on the entire railroad. The use of some sort of flex track is almost a necessity to re-create those broad curves and smooth transitions into the curves. Even with the widest curved sectional track available, it might be difficult to achieve the same feel. It's definitely one of those layouts that was easier to sketch on graph paper than to actually build, particularly with sectional track. 
Jim
