Update: I drove this area and I beleive I've got the best "detour." If you are taking I-70 West out of Indianapolis to Funfest, follow these directions:
After I-465 on the west side of Indianapolis, follow signs towards Ronald Reagan Parkway (you'll probably see signs for the airport first, and that is fine as well, but eventually, you want RRP). I drive this every day and call it the world's longest on ramp - it is a few miles long, as it runs parallel to I-70 for quite a while. The advantage of the length is that you can easily see I-70 to determine if it is backed up without getting caught up in it if it is.
After you pass the airport exits, the actual exit for Ronald Reagan will be next. By this point, if you're not seeing a backup on I-70, get over to the left and it will lead you back to I-70 itself and you'll be on your way.
If 70 is backed up, take the exit for Ronald Reagan. It will exit you to the North. The first light you come to will be Stafford Road - turn left here. If you watch for the "Adopt A Road" signs, you'll see my company, OHL maintains this stretch. I hope it looks acceptable (I need to get out and work some of those weeds!). You will follow Stafford about 2-3 miles to the 2nd light you come to - this will be State Road 267 - turn left here. This will lead you back to I-70. All of the backup may not be done at this point, but I beleive most of it will be and you will have saved time by missing a few miles of it.
Good luck and hope to see you there!!
Lastly, regardless of traffic conditions, know that cops like to hang out in this area speed trapping often.
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