The Internet enables writers to connect with their audience, promote their books or brand, and network with industry professionals in so many different ways now. So. Many. Different ways. And still, almost everyday some Marketing guru out there is touting the next new exciting digital thing that'll supposedly revolutionize EVERYTHING! How often have you thought: It's too much!?
Honestly, it is too much especially considering that most writers have a career and/or manage a family, must find time to write between the first two things, and have to invest time and energy in their own marketing and promotion. So no, you probably won't be able to do it all. You need to tailor your digital strategy to your life and commitments to truly be efficient and worthwile, but that's a discussion for another day.
However, if you do just one thing, then you must have blog or a website. I feel a blog is less of a hassle to throw together if you have no experience in web design and allows for a more open and transparent channel of communication between yourself and your audience so my recommendation is to keep a blog over a website if you do only that one thing. There are so many professional looking free templates out there that it won't be too much trouble finding one that suits your work and personality. Even after all these years, the blog still the most important thing you can do to market yourself. And yet, it amazes me how often writers don't have or keep up with their blogs. Think of your blog as the foundation stones of your online platform that you will build up from.
But a word of warning: you mustn't let the blog be all about selling your books. You won't build a committed audience if all you do is pitch your book at them. You have to let your personality shine through. Now if you're uncomfortable with that level of online sharing there are other alternatives. Build your blog into a resource pertaining to something that will interest your intended audience. It can make blogging a bit more fun too if you're delving into your own passions and interests.