If you are going over a particular subject with the family and feel that a field trip would be beneficial, then that's what you should do - go for a trip. If you are attached to a support group, you can plan to include other children too.
Here are some guidelines that will help you plan:
1) Collect the rates
2) Allowed ages
3) Special highlights
4) Size of the group
6) Eating facilities
Inform your support group of all these details well in advance so that the necessary circulars may be sent out. On the appointed day, arrange to meet with other parents and children in a particular place. Plan the mode of travel and reach the place at least 10 minutes in advance.
The field trip is not just fun. So, let your kids bring their writing material. Allow them time to stare and admire. Do not hurry them along. Collect data beforehand so that you can clear doubts. Get help from a guide, if necessary. And most importantly, have fun and enjoy the time you spend with your children.