Originally Posted by dcl

I understand what you want to do: You don't want to go to a university and pursue a formal curriculum of study. You simply want to follow the fastest possible path to an understanding of what gravity is and how it works. I suppose you could follow a plan something like the following:

Find a good book on general relativity, one that derives the Einstein field equations and explains what they mean. There are a number of such books around. You could start to read it. You would very quickly discover that you need to be conversant with tensor calculus, the form of mathematics on which the Einstein field equations are based. They relate the Riemann-Christofel curvature tensor to the stress-energy tensor. You'll find that you need to learn about tensors and calculus, so you'll need to look into each of those fields before you can begin to make any headway in learning how to understand the requisite tensor calculus operations. So you need to set the general relativity book aside and find books on tensor analysis. When you start to look into tensor analysis, you'll find that you need to learn calculus, specificially differential calculus. For that, you'll need to learn analytic geometry and algebra. You'll also need to learn elementary physics to deal with the physical concepts that you'll encounter in the book on general relativity. For analytic geometry, you'll need to learn algebra. I've probably left out several secondary subjects you'd need to learn such as determinants, matrices, and trigonometry that you might tun into along the way.

I can assure you that it will be a long, hard process consuming a number of years, but I see no reason why you'd not be able to do it if you have sufficient interest, aptitude, intelligence, determination, and time.