If all you want to do is get it "about right" then the following rules of thumb/hints might get you started.
1. Lift curve slope: classically, 2*pi per radian - which is close enough to 0.10 CL per degree for a rough guess. Use a wing area that's about right for the physical wing - not whatever BS number the designers may have concocted.
2. CLmax. If you can find an approach speed (vref) at MLW or takeoff speed (V2) at MTOW then assume they're using reduced reference factors (1.23 or 1.13 respectively), calculate the 1'g' stall speed that results, then use that to work out a CLmax for the config.
For clean config, find the best long range cruise speed, and assume it's at about 1.3-1.35Vs for the config. Back out Vs and hence clean CLmax.
None of those will be the right answer - I can hear the gnashing of teeth as I type - but they'll get you started. At least you'll have something that vaguely resembles the aircraft in question.