A Catholic wedding is completely different without the mass. The only response that people other then you two will have to say is
1. you dad will have to give you away by saying we do (or something like that)
2. There will be the three normal readings plus the responsorial psalm
3. Peace be with you(s)
4. And Amens after the opening and closing prayer.
You can always include the responses to the readings and the psalm in your program.
There is no kneeling for your guests or long prayers. it should be fairly painless