I do this 7 Saturday's every fall, so here's the word ...
Park in public ramp, 2 blocks south of Sheraton on Dubuque St. Last year, it was total honor system whether you paid or not. This year, have had to either pay an attendent or the machine to get out of the gate. Still, 1st hour is free.
(The IC Parking Gestapo quickly realized (much to the chagrin of their socialist, altruistic ideals) that, when given the option, it was about 50/50 collection-rate and, while reliance on human integrity, independent of consequence, is a worthy societal promotion, it's more important to pay for these expensive structures ... but I digress.)
From there, it's right at 1 mile to walk west on Burlington to Kinnick. Of course, allow 10 minutes to pick up a tall canned beverage at Kum and Go, to drink on the beautiful (yet, quite smelly) walk across the Iowa river and up the hill ... Again, I digress.
You now know you need 15 minutes to walk back to your car from Kinnick, whenever you decide to leave.
(I strongly encourage you to write that down; it WILL be handy knowledge to retain.)
Turn left out of the ramp, turn left again and get back to Burlington St. As OLWOMPAWORM referred to, above, head east (the direction, not the awesome 70's rock band with such hits as, "Since You Been Gone" and "Never Been Any Reason") toward Hwy1 / Governor St, which is the 1-way, going north, out of town.
Stay on this 1-way, Governor St, north, until it finally rejoins with Hwy 1 at a stop-sign. -- it seems to take forever but is only about 1-1/2 miles. Turn right, and, of course, allow an extra 20 minutes to stop for a post-victory celebratory beverage at Hilltop Lounge (aptly, though a bit presumptuously named because, while it is near the top of the hill, it seems to me that the actual peak is located a bit further north.) While you may have sanitary concerns, it is extremely unpretentious with a very good selection of draft and bottled craft beers. Damn! Another digression!
From Hilltop [sic] it is a mere 50 - 55 minutes to Brady St exit, in Davenport, depending on your speed and bladder (which depends on the volume at Hilltop [sic])
So, total Kinnick to Davenport time is approximately 1 hour, 45 minutes, if you navigate the route properly, as I've directed. This allows 5 - 10 minutes grace to get to the church in Davenport.
Happy trails.
