Brian,
Congratulations on your second child. We will be having our birth in the next 2 or so weeks, so I can sympathize with your position.
I humbly submit that having two children is really not that much difficult than having one, though there are certainly some logistical issues to work out. As long as you and your wife are committed to providing a loving, nurturing, Christ-focused home to your children, you will be fine.
A couple of other things that may be helpful in the remaining/upcoming time:
1. If there are any things that your wife is really wanting done before the baby comes, try to do them. This will likely help your wife to feel loved and can help to relieve underlying anxiety she may be experience from loose ends.
2. At the same time, make sure you are spending lots of quality time together with your wife before the birth. It will be a lot harder afterward.
3. I would recommend being the one who gets up with your older daughter so that you can help your wife rest and heal. Your wife (and you) will be getting up a lot to feed/change the baby during the night. A way to honor your wife as the weaker vessel is to be the one to get up with your older daughter when she wakes up so that your wife can rest longer.