If you are going to stay around the shipping canal, definitely try Sawyer Harbor, at the mouth where it meets the shipping canal. Lots of smallies there caught on crankbaits. I fished there a couple of years ago for 5 years straight and did well there, also don't forget to fish inside Sawyer harbor. If you don't find them inside the harbor, then don't waste a lot of time, cause they aren't there, they will be on the outskirts. I also fished and ventured out of the canal towards snake island. I watch the weather religiously, and as the day went on, the wind started to pick u-p. I had a 17' alum. fish-n-ski, and on the way back to the launch in the shipping canal, I was haulin' **** as I saw the weather get progressively worse. Made it in time, but I was never in 3'0 waves and it scared the crap out of me.
As far as the lower dells goes. I never tore up a prop running the river, however if you don't know where you are going, then I guarantee you will tear it up. A lot of shale shelfs, and rocks when you come to the dam.. I always stayed at the River's Edge for the weekend. Most of my boat damage was from the boat banging up against the dock when it was tied up, or guys, not knowing how to maneuver around a river that has current, and they hit you as they try to tie up to the dock. Many times I didn't see this as I kept my boat tied up all night on the river. They rent boats there and a lot of guys are careless. Best to take your boat in and out and launch every day. Saves a lot of aggravation. Going up to the dam from the Rivers Edge, stay in the middle until you start coming up to the dam. If you've never been there take it slow and watch the water levels, look over the side of the boat frequently to see how shallow you are and look at the can buoys in the water they will show you where the low spots are. Again don't go flying around the river, especially going up to the dam. As you approach the dam, watch where everyone else goes, and take it slow. It is beautiful up there this time of year. Now going down river past the Rivers Edge, towards the cable, not much to worry about. Again go slow. I would assume that the dam will not be fully open, so you should have some good fishing, as the current won't be as bad.
As far as fishing for walleye, sauger and smallies, I have found the best to use out there is 3/8 oz round ball jigs tipped with a fathead. jigged on the bottom, like they fish the Wolf River. You must keep your jig in contact with the bottom as the river fish hug to the bottom on the lower Dells. Operate your electric trolling motor with your foot, and bounce two rods one in each hand, on the bottom. You will find them in slower moving water. I have also had better luck with pink jigs. Bring a lot of jigs, not bass jigs, as you will lose at least 12-24 per day, if you are not bouncing or dragging jigs you will not find the walleye. White and yellow chartreuse works well some days also. I love that section of river and have always done well there. However now I have a fiberglass boat, and It would kill me to see it get damaged. You can also anchor, up river and cast into the river. That works well sometimes also. I found moving around with a trolling motor works better. If you need more info, you've got my number call me.
PS: As far as using your GPS to run the river, use your eyes and judgement. GPS is only good for about 10 feet either way. The River is not that wide, so have guys look over the sides as you drive and go slow. I may be over protective of my boat, but you don't want to hit a shale shelf going too fast. It will shear your whole bottom off. I don't want to scare you but it's better to be safe than sorry. Once you drive up and down a couple of times, You will get used to what spots you can run.
Good luck ,good fishing and post your fishing results when you get back. Looking for your fish stories. LOL