Does your preschool take them? Do parents have to be there? Does the preschool provide transportation if needed?
DS1's preschool takes a few. Recently they went to the library which is within walking distance from the school so they went during class and parents did not have to be there. The rest of the field trips are also in place of class time (classes are AM or PM so trips are only a few hours). However, they are not within walking distance so the children are to meet at the location instead of at the school. A parent or other chaperone must be present for the child to attend however no siblings are allowed.
DS1 was supposed to go on the upcoming field trip. However, I just found out that DH's work schedule chanced and we can not find a sitter. I feel bad for DS1 because he was looking forward to going but am planning on calling the other parents with younger siblings to see if they want to have a play date if they weren't able to go as well.
Re: Preschool Field Trips
DS's class has gone on 3 field trips and they rode the school bus. 2 trips were local and during class time(fire house and a train display in town at Christmas time) They also went to the pumpkin farm. They had several parents as chaperones. This was an all day trip(left at 9:30 and back at 2) so the AM and PM classes went together.
Maybe when you call the classmates to set up a playdate, one of them will offer to take your younger one instead?
DD's school does do an annual field trip. It's typically in May (right around the middle of the month) and parents do not have to be present in order for the children to attend; although, most parents make the effort to go with their child. Transportation can be provided if need be.
DD has about one field trip a month. Her first field trip was to a location around the corner, so they walked to that one. For all the other field trips, they've taken buses. We do have to pay extra for the bus transportation, usually it's about $15. Parents sign up to chaperone field trips, on field trips they require one adult for every two kids.
ETA: Chaperones can not bring siblings and only the 4 year old classes go on field trips. DS (3) goes to the same school and his class does not go on field trips.