Blackbird!!!
It has to be challenging fly that huge amount of titanium at mach3+, managing the engines, in flight refuel and feeling the plane stretching for the extreme high temperatures.
Taking pictures of secret enemy sites will be great!
And yes, it's all analog so it's maybe simpler to produce in DCS.
http://www.nmusafvirtualtour.com/media/068/SR-71A%20Front%20Cockpit.html