I'm quite surprised at the suggestion that an experienced builder would start this project without plans.
My experience is that the more planned and detailed the plan the faster work goes and the less problems encountered. After jumping into things a few times without a good plan and winding up with a head scratcher that cost me time or money, I learned the value of planning.
For my personal projects I detail every one of them on AutoCAD. And they're detailed down to the fasteners. I even drew the family picnic table into AutoCAD. Then I have an easy time with the bill of materials and can easily generate a cut list. No running back to the supply house 7 times.
In fact, for my house addition and renovation, my plans were so clear that the building official let me go without an Architect or Engineer stamp on it. That alone saved me $2000. If I went in and told him "I've built it all, I don't need a plan" he would have laughed me out of his office.
Perhaps the poster is looking for architectural plans. Heck, I know how to build a garage, but when it comes to siding choices,shutters, and architectural flair, I run for cover. Maybe he is looking to run power and plumbing out there, or looking for a plan with some divided spaces (ie workshop, bathroom, welding booth). Again, when it comes to making spaces work, I have to hand it to Architects. This is one thing that they can do.
The poster lives in NY. He can't very well just put anything up. He needs to be concerned with snow loading and various code issues.
We all have our comfort zone, but I wouldn't scare the poster away from this project. It's do-able for anyone that knows how to swing a hammer, and needing plans isn't a signal to scrap the idea.
Not a very welcoming post to a new member.