I think it's just a matter of what's important to you. Being cheap is completely fine for me on most everything, but if I don't spend on things that matter, then I'll be unhappy. Unhappiness is never worth it to me. For me the two things that matter are travel and food. That's not to say I'm not cheap about the parts of those things that matter.
As for the specific question: My wife and I combined spend (and make) almost exactly twice what you spend, and our travel budget for this year is $9,700. So you're good in my book.
I've done couch surfing, (both hosting and staying) and highly recommend it. It definitely takes some advanced planning, especially if you're a single guy, to find host, and there's a pretty short limit on how long you can stay, but it's a great way to meet people, and it's free.
I've never done AirBnB, but I know people who swear by it, I'd definitely check it out.
My biggest recommendation though is camping. Obviously may not be your sort of thing, but I've had a great time camping in europe. My wife and I were in Europe for 15 days last summer and camped 11 out of the 15 nights. Saved a lot of money, though we sunk most of that into food and wine.