This mountain rises out of the Mississippi River and has been a navigational landmark for centuries. It is the northwest "cornerstone" of Perrot State Park.
Last September I brought a kayak and paddled over to Trempeauleau with the idea of climbing it. Paddling from the boat landing on the waterway that surrounds it to get on its northeast side was very tiring (a surprisingly strong Mississippi fed current existed), and I landed in what looked like a promising spot but ended up in very wet mud up to my thighs, which ended the attempt. I was looking for a clean landing and maybe a use trail, but did not find one. Maybe another time.
Here and there, I have read about climbers who posted an ascent of Trempealeau. But, not very many, though. What you describe is part of why I canceled my plans to attempt the same last year. The heavy vegetation coupled with a rattlesnake population (common along the Mississippi River) that generally cannot be seen until you are virtually on top of them is also a concern. Seems like a winter ascent might work best, right after a dry autumn perhaps. What it takes to reach this summit is rather atypical for this region of the USA and perhaps epic on a small scale. Your attempt and comments should be helpful to anyone else considering Trempealeau Mountain.
I did not know about the rattlesnakes! Maybe I was fortunate not to find a landing spot.