OP really hit the nail on the head -- one of the hardest parts of the time off is not having work-related goals and being OK with it. When you're employed it's easy to spend time imagining what you'd do with your time off. When you have this long stretch of time off, it's hard not to think about work. I was ashamed anytime my mind would drift to worrying about "what work will I do next?". In the end I think this is natural and OK, but it's important to fight the urges.
However, I don't agree that you should have 0 goals. You should have personal goals, just not work/career related goals (and OP kind of means this).
All of those non-work things you told yourself you want to do? Now is the time to do them. Travel the world, go backpacking for weeks in the woods, live out of your car, read too many books, appreciate art, volunteer. Take chances and explore.
The single biggest question you come to terms with in your time off will be "Who am I?".
You'll realize that since childhood you've always been working towards career/life goals. Get good grades in K-12, do well on SATs, get into a good college, choose a good major in school and work hard to learn, get internships, get that perfect job, work your way up the ladder in that job, get married, buy a house, have kids, make more money so your kids can repeat this cycle.
When you take the time off without goals in the typical "life flow" you'll have moments of existential crisis because you're not doing what you're "supposed" to be doing. These are important times. Learn to embrace the feeling. Smile and remind yourself that you're not doing what you're "supposed" to be doing because you're doing whatever the hell you want to do.
Just don't squander your unhinged time. Spend it wisely exploring the world and yourself.
When you get back to the "real world" you'll never see it the same again :)