I would discuss this with your prospective surgeon. My understanding is that bariatric surgery imposes severe dietary restrictions forever after. At a minimum, I would expect you will have to drink more often to avoid dangerous dehydration. You may also need to use easily digested foods like energy gels, but that's a guess on my part. Your questions are good and you definitely should get answers from the doctor before you decide to do this.
I expect that very, very few patients of bariatric surgery are cyclists. I can't recall anyone here claiming to have had the surgery. I'm surprised that someone who can ride 65 miles would consider it, but that's your business.