I am attempting to put a solid floor down for the detached garage I have at the home I just purchased. It will not be used for storing cars, but will have a weight bench and lawn movers, etc. so it will need to be fairly solid. It is a wood structure with about 2 feet of brick as a foundation. The roof and foundation are solid so with a little work to the walls and door frame there will not be a lot of water getting in there. I plan to use some patio pavers to lay down a floor, but I am unsure of how much base I will need underneath that. It is a fairly large area (14' x 14') so any digging and gravel laying I can save myself will really benefit my back. So given the fact that this floor will not be holding any cars and will not really be exposed to the elements to need much drainage, what kind of base layer(s)of gravel or sand are the minimum I will need to have a solid, long lasting floor?

I made a 8 X 12 shed using patio pavers for flooring. I did it on the cheap and didnt't do anything for the base except level it and put down a weed block fabric. All I used it for was my garden stuff, mower, edger, and some wood storage.I had it for about 15 years before I moved. The last time I was in that neighborhood it was still standing and did survive a hurricane
So I think what you want to do is feasable so long as you dont decide to temporarily keep a car in there

You can do it that way but I personally wouldn't use the weight bench on it. Just my opinion.