Our family joined 4H for the first time last fall. We live in Wisconsin.
Our 14 year old is a "regular member". Our 9 year old is an "Explorer". Our 7 year old is a "Cloverbud". The group we joined is family-oriented, so our entire family attends the monthly meetings. Our 5 year old thinks he is a "Sprout" and the 3 year old also thinks she is a member. ;) During the meetings, the little children sit with my husband and I off to the side.
Our Cloverbud was given an activity book to work in, courtesy of the UW-Extension. She could complete it and enter pages in the fair, or just keep it for her own enjoyment. The UWEX gave the same book to our Explorer *and* our "Sprout". :)
Our Cloverbud was able to enter items in the County Fair. Every Cloverbud received a green ribbon for each entry, as well as a small trophy. Her entry (she only did one for our first year) was "judged" by a high school-aged 4-H Member from another club who was very encouraging and positive. This helped to give her an initial experience with judging without any actual critique.
As for scheduling, our club (like most) meets once per month. It is very easy for us to commit to that. Our goal for this year is to complete one fair project per month and the children can then choose which projects they actually want to enter later.
Project books, if not readily available through your club, can be purchased online at http://www.4-hmall.org/ very affordably. Our UWEX provides free project books for many topics. We borrow them, glean from them and return them for another family to use. In our county, if not in the entire state, you are not required to follow the format of a project book.
Occassionally, there is a separate activity for Cloverbuds in our group. I prefer that our daughter stay in the regular meeting, but if a separate activity is planned, we let her go. They are always in the same building, but in a different room, led by another Cloverbud mom.
Your local UWEX office might be able to share which local groups would be a good fit for you. You can ask about groups that share your interests, have a good number of Cloverbuds, are primarily made up of homeschoolers or whatever deciding factor you may choose. We are the only homeschoolers in our group, but that has not been a factor.