I wouldn't worry too much about the midwife not arriving on time for your first baby. It's possible, but it's really unlikely for a first baby. Heck, it's actually pretty unlikely for any baby, but especially a first. My helpful advice is something that a lot of people probably disagree with, but having had three babies, NONE of whose births went anything like I anticipated, I think one of my best pieces of advice is not to overly plan anything. Just don't get any ideas in your head about how it's going to go, because you never know. My first daughter was born at 38+1, when I had fully anticipated going past 40 weeks. I planned on pushing in a squat or on hands and knees, but both of those positions felt horrible when the time came and I pushed on my side. Since she was early, I expected my second daughter to be early, but she was born right on the EDD the OB gave me and a couple days before the one the midwife gave me, so not early at all. She was really fast - a lot faster than I expected. I ended up having her in the tub, lying almost flat on my back because she was so fast and it hurt so much I couldn't move. I never wanted to push flat on my back, but that's what happened, and it was my choice. My third daughter I expected some time between 38 and 40 weeks, but she came a few days late, and I had her in the (empty! - I made them drain the water because I hated it) bathtub after spending my entire labor pacing my house (I was quiet and didn't want to move for my other labors).
Basically, my point is that every labor is different, you can't control what will happen, and overly planning things is likely to result in you being disappointed if it doesn't work out how you anticipated. Just go with the flow. Have some music you might like, have some snacks, have some comfy clothes for if you want them, but plan that you might also be hot and naked, then know that you will do whatever feels best when the time comes, and it might not be anything you anticipated in advance. It will work out however it will work out. Don't sweat it, other than reasonable planning. :)