Yay for first birthdays!! I would think that no entertainment is just fine. As long as the kids have access to her toys they should be fine. It may depend on exactly how many kids you're having and their exact ages, if you have a lot between 3-5 you may consider doing a craft, but you're probably just fine without one...especially if most of the kids are family and hang out together usually anyway!
I would suggest opening presents at the party. People are really excited about what they bought and they want to show it off and make sure you see it. Have your kid near you, if possible, while opening and see if you can get her to play with the wrap, bows, tissue, etc. If she crawls away...oh well, just keep opening! ;)
Also, I would suggest doing a low key lunch that you don't have to do much for. Costco and Jimmy Johns both have really yummy and reasonably priced sandwich platters and then do some side dishes, etc.
I always do a little party favor for the kids, but that can be optional, especially if they are mostly family (I'm not sure, but sometimes 1st bdays are). I usually do a theme and make the food and favors go along with it, but I have a tendency to be a bit over the top (you should have seen my daughter's 1st birthday...a doosey...but I love it!)
Most of all just have fun and celebrate that the first year is behind you! It only gets better!