KD4UPL,
Might be wise for this trip since you will be in Michigan the last of July. However, plan on coming back again with your family (you'll be very happy you did) and feel free to PM me so I can help you with your needs and questions. We know the area extremely well as we've lived here for over 73 years. Yes, it's a very big crowd during the Coast Guard Festival but a very friendly bunch always and the events are very spreadout around the local area so it's not a zoo of traffic other than the last 2 days (Friday and Saturday in August) as there's a few hundred thousand in town those days alone. Lots of school busses are used also to shuttle visitors to and from the large parking areas not right in downtown area. Also there's 4 open air trolleys and 32 Harbor Transit busses that are very cheap to ride. The city/area has been having this festival for 91 years now and they are fantastic with handling so many people efficiently. Takes over 1100 people and volunteers plus the State Police, sheriffs, city police to make it clean fun for all who come to the festival and the same people come back year after year so they must really like it!
Not a problem for us at all as we always rent the same 3 parking spaces (the last 27 years) right on the waterfront across Harbor Ave from the Municipal Marina and we have the "best seats in the house" for the final thurs/Fri/Sat and stay right there in our Lance TC. One space for the truck/TC, one for our carpeted patio, and one for a place to park our SUV so we can go places without moving the RV. Used to take one of our 5th wheels down there but don't need that much room for just 3 days and we're only in it at night mainly. About 30 some RV's rent spaces where we are and some rent for the whole 10 days. One HUGE Party and for all ages!
It's a fantastic time with a huge carnival stretching down the main street, a 2 to 2-1/2 hour parade within 3 blocks, a big street dance with a very good name band with music from the 1960's all the way to today's music, several programs/events and dancing also at the waterfront stadium only a block away, The Worlds Largest Musical Fountain since 1962 - the same size as a football field built on the face of the big hill/dune across the river with brilliant nightly programs/performances, several Coast Gurad ships are here and have free tours for the public and the kids just love it, free concerts in Central Park and other parks too, 7 large "beer tents" with live bands/dancing to enjoy right in the area, and the Saturday night finale gigantic fireworks show shot up directly across the river from the hillside below the musical fountain so we are nearly right under them when they explode. They cover the sky with brilliant displays for over a quarter mile wide, lots of other things too. Only part of what goes on just during the last 5 days alone.
Extremely handy for us as my wife is disabled but not wheelchair bound and she can use her electric 3 wheel scooter to whiz around the downtown events as they are mainly there the last 5 days.