Fit where? - floor space or height constraint, or reach requirements?
Simulation software is the way to go if the task is complex or you are uncertain of the reach (but the software costs a lot of money - so not worth buying yourself for one robot, but there are specialist companies with the software that will do the simulation for a fee)
if it is a simple pick and place operation that is easily within reach then you might get away with drawings of the robot footprint placed onto your workcell layout, as long as you dont mind possibly moving the robot / fixtures a few times after they have been bolted down, if the robot cant reach.
Are you the final customer?, if not they might have standards dictating which simulation software you have to use.
R2000

? which one (there are 19 different models in the R2000 robcad library)
r2000ia125l.co
r2000ia125l_if.co
r2000ia165cf.co
r2000ia165cf_if.co
r2000ia165f.co
r2000ia165f_if.co
r2000ia165r.co
r2000ia165r_if.co
r2000ia175l.co
r2000ia175l_cable.co
r2000ia200f.co
r2000ia200f_if.co
r2000ia200r.co
r2000ia200r_if.co
r2000ia210f.co
r2000ia_100p.co
r2000ia_165ew.co
r2000ia_200ew.co
r2000ifo_200_rj3i_b.co
2D drawings should be available from the fanuc website (if they are anything like any other robot builder), if not ring up your local fanuc rep and say you are thinking of using their robot and can you have the drawings for it to see if it will do the job you want it to do. if they say no to a reasonable requerst like that what sort of support are you going to get??, consider a different maker...