Avoid using children under six (6) years of age. It may be emotionally wanted but any child younger than six does not have the attention span to last four hours that a wedding takes. Learning what to do, then standing still for 15 to 30 minutes during the ceremony, may be too much to ask of a kid that young. Ability varies child by child but be aware of it.
Groom and groomsmen take around 30 minutes to get ready. If they arrive at the same time as the bride then it is possible for the photographer to take pictures of the grooms while the bride is still getting ready.
After the wedding ceremony is over the complete wedding party pictures are taken. Immediately following the reception line everyone involved in the wedding should return and allow at least 20 minutes to get group and individual pictures taken. This is why, as noted above, people in the wedding party should not be in charge of the site setup, reception, teardown or any other operational wedding needs. They need to be available to have their pictures taken. If they are busy working then they cannot expect to have themselves included in the group pictures — or any other pictures.
The bride and groom should NOT have any tasks to do on the wedding day. Other than showing up and exchanging vows, they should NOT have do ANY physical tasks.
This is especially true AFTER the wedding. They should just enjoy themselves. If they change into regular clothes after the ceremony the only thing they should concern themselves with is getting into their car and going away. No teardown, putting items away, cleaning up or ANYTHING like that. That just distracts from their wedding day by making them think and work when everyone should be doing that FOR them.
If any special pictures are to be taken write them down in advance. The photographer does not know everyone nor can he / she read minds. With a list, and someone to point out who is who, then the photographer can take the pictures desired. This is another reason to have someone designated outside the immediate wedding party to coordinate the event.
Groomsmen, like fathers, shed their tuxedos in half the time it took them to put them on. The longer you wait to take pictures the less likely they will still be dressed like they were during the ceremony. This even applies to the groom at times.
Don't delay between wedding stages:
The longer the delay between the wedding stages the more people leave. Immediately after the ceremony some people will always leave. While the reception is being set up (or while people are traveling to it) is when the complete wedding party pictures are taken. Allow 40 minutes for group pictures, property collection and travel time to the reception location. Now the reception is going on. Once the bride and groom arrive at the reception people get to eat. It takes 15 minutes or so for the people to go though the food line. Wait 5 minutes after the last person has gone through and cut the wedding cake. The toasts can be done at the this time since everyone is gathered around. Now wait another 15 minutes and do the first dance; wait another 10 and do the money dance, another 10 and do the garter / bouquet toss. This means from the end of the vows to the bouquet toss around 1 1/2 hours has elapsed. About the limit for most people to stay in one place. 1 1/2 hours is the same length of time as a standard movie. Now regular mixing, saying hello and dancing can occur. After a 1/2 hour to 45 minutes of free form entertainment all the presents should be opened. By this time only 1/2 of the guests can be expected to still be there. Mainly those who brought gifts!
Rent a car:
If you do not want your personal car to be decorated then rent a car for the weekend. I don't know if the rental firms charge extra for cleaning. This is good if you are going immediately away on a honeymoon the next day. No worries of cleaning the car, no parking fees at airport etc. Just drive and go. If not traveling away, but going to a local Hilton, Doubletree or other premier hotel then renting a limo would work. The driver will not allow any decorations on his vehicle of course but you can go in style. Limo prices vary from $80 / hour and up.