How to move large number of sims across cities?

[errantry 0]

I'm trying a new style of play, where I have connecting cities, one specializing in IHT and one specializing in CO. Both cities are fairly large (100K each), so I need to move about 50k people between the regions (I know this isn't very realistic). How can I do this efficiently? I try connecting them with one highway, but the on/off ramps become horribly jammed. I try using the simulator Z park and ride mod, and make the sims take subway to the train, which goes across the region, then have them get on the subway again to their location. This doesn't seem to be able to move very deep into large regions, where my city edges gets abandoned to commute (which doesn't occur with highways before).

Is any way to do this better, any mods or anything?

[Riot55 2]

monorail, train and what about elevated rail?

simulator Z has NO sims driving in my city aside from a central parking garage.. its nice, but also unrealistic.

what if you had two monorails?

red line and blue line with modded/high capacity stations?