Ruby, as a language, is reasonably compact, and certainly not a big jump for someone with any amount of Perl and OO experience. Rails, on the other hand, is a big framework. You can learn the basics in a few days, but much like PHP, you really can't master the ins-and-outs of the full stack without (at least) several months of regular use.
It's also a moving target: new APIs fade in and out of existence with pretty much every release, and many "best practices" (early RESTful routing, anyone?) are picked up and dropped pretty much according to the whims of DHH and the other core committers.
That's not to say that it isn't worth learning, of course; if you're willing to commit to using Rails pretty much full-time (and work within its limitations) for the bulk of your projects, it offers a lot of great infrastructure to build on. Since it sounds like you want to focus on solo development of web applications, Rails may be just about perfect for your needs.