I guess the question is how wide are you? Less than 18" is pretty narrow for basically walking sideways for what looks like to be 6' or so. Even if you can fit it is really easy to snag clothes on scenery or whack things with your arms regardless of how careful you are. I had a 16" access aisle once and that's what I did a lot.
Since you will need to go in and out sideways, if you do a hinged section it should be hinged up as down will take a few inches in width. Even better, would be a gate that swings out into the rest of your room. A lift out could work, but you will literally have to twist to put the section back in and if its of any weight or awkward size (basically keep it small) and that is always a risk for a lower back injury. If you absolutely need to keep the narrow entrance, you can always sit on a castered chair and scoot yourself in and out.
Peter
