Hey Fishface! Welcome to the board!
My short answer to your quesion is….yes.
Did you have a certain cat that you were targeting or just cats? I’ve never fished the MN river…but that’s going to change this year. I’ve only fished the Miss once for cats although Dirk and others pull out some awesome fish. I’ve only fished the Croix 3 times for cats. Skunked once and two 7 to 9 pound flats the other times…but there’s bigger ones out there.
So…it’s really up to you. I think the (I hate using this word) easiest of the three would be the Mississippi, (to find spots). The Croix has less snags and I can’t say much for the MN…but other, more experianced cat men will.
Good luck were ever you go…and remember to take a camera along…or at least let us know how you did!