Improve Regional Mass Transit First!
I live in the suburbs, adjacent the UP-West Metra rail line. My kids love coming to the museums, but we almost *never* use mass transit because the timing of trains during the day is horrible! It takes over an hour to get downtown, and the mid-day train schedule is so sporadic, you're either stuck downtown far longer than you want, or you have no time to enjoy the facilities. There are already plenty of buses to get from the rail stations to the Museum Campus. The problem for many suburbanites is that the rail service itself is prohibitive to museum use.
Perhaps a solution would be to negotiate special trains on each line that would have "express" service downtown, and arrivals/departures would be timed to coincide with shuttle buses to museum campus. Make it as easy as possible. For example, each rail line could have a specific time in the morning, say 9:30, where certain stops would be accessible. So, take the UP-W for example. There could be a stop at Wheaton, Lombard, and Oak Park, for example. The train would be a short train, just 5 cars perhaps, and it would arrive around 10:15. The bus could be timed so it leaves Ogilvie (off of Clinton) and heads straight to the Museum Campus loop. It would be free if riders show their Metra daily MUSEUM CAMPUS pass. There would also be specific return times, perhaps once per hour, that would take you back to *the same place* at Ogilvie (to avoid confusion) and there could be better signage to help newbies find their return train. The return would also be an express to the same stations.
I recognize that this plan is costly for Metra, but it would surely be LESS expensive than building an expensive Light Rail system that people from the suburbs don't use anyway because they already drove their car downtown!