I'm preg. w/ #4, and I'm having those same symptoms as you, but they come and go. When you're in *active* labor, you will know it. The sensations you feel are more intense, usually all around the belly/back and not just in the front. You know that it's real when you change positions and things still stay consistent and when things continue at a somewhat regular pace for over an hour. I think the usual rec. is contractions come every 3-4 min for over an hour. Then you know it's the real deal. For me, several times a day it seems, I have times where I'm like "that felt different/more/real" and it goes on for a bit and I have a few contractions or sensations of whatever it is, and then I get up or move or it just stops. So I know it's not the real thing.
with my first, my water broke first, and I started contracting and I thought those were the real deal, and yes they were regular, but all day long I had them and about 12-14 hrs later my mw's came to check me, and I was still very "happy". I started pumping w/ a breastpump and instantly I felt like "OH!!! I see what strong contractions feel like!" It was instantly "more".
Anyway, I'm rambling of course. I'm just saying that you will know when it comes.
And you'll do fantastic! And hey, if you can ignore the annoying early labor stuff, then that saves your mental and physical energy for the active labor stuff.
I want to hear about this birth cabin deal--sounds awesome! Are you far away and that's why you go stay before the birth? Good luck and have fun!!