Assuming you could ride the expressways legally, how would this change your riding? For example, what trips would you make if you were allowed on the highways that you wouldn't choose to make otherwise? I'm thinking it would be easy to cruise to Huangshan or 1000 Island Lake, heck even make it to the beautiful areas of south Zhejiang province from Shanghai.

The expressways have the main advantage of fast traffic flow with little obstructions, and they are safer. The surface roads seems to take 1.5 times longer, even more, and there is more danger with more obstacles to avoid.

Another way to look at it, would you still make the long-distance trips if restricted to surface roads? It seems that the majority of ride reports on this forum involve exactly that and it's a reality that most have accepted, however begrudgingly.

On the other hand, there is practically zero risk of being stopped by the police with unplated bikes or fake plated bikes if taking surface roads. The tradeoff seems to be you can ride wherever you want illegally, but the expressways are truly off limits.