I don't care that this is a late and buried reply and most likely only you will read it. I even created an account just to reply to you. I did this because I was you about a year ago and your post is exactly something I could hear myself say or think. I had a good friend that had lived part of their life out in the big world and I was talking to her about it, explaining how I felt, which is just about what you write in your post. It ended up changing my perspective a bit and I actually finally just did it: I quit my very nice job, girlfriend quit her nice job, we sold the car and left to travel the world. We are still travelling, and are going to continue doing so for at least another couple of month.

Reread your first paragraph, then reread your second paragraph. To paraphrase them both a bit: "You would like to experience some real adventure, but getting stuck in the mud doesn't really appeal to you". Hmm?

The only way you will experience something that is really fulfilling to you in this way, is if you go do something that you are not really all that comfortable with. Go do it and feel how you are not only a better version of yourself, because you know that you can now "do this too", but it also changed your view on the world just a little bit. It broadened you character and your perspectives a bit and THAT is fulfilling.

It doesn't have to be mud in Africa, but it does have to be one of those things where some part of it doesn't really appeal to you. The only fulfilling adventures are the ones that change you, and an experience can't change you if it is designed to only give you what you already know and like.

You don't have to do that one big thing. You can do a series of smaller things instead. As long as they challenge you it will be fulfilling overcoming that challenge.