what kind of venue?
Lots of space, outdoor and indoor (like a village hall). The sort of space we can store stuff from week to week, but also where we don't have to make it totally spick and span before we leave. Has a kitchen with functioning stove, microwave, kettle.
what kind of hours?
You'll never get this right :) You just have to go with what suits your core people. 10-230 can be good - makes it doable for people with other children in school.
Specific to age group of your kids or all ages?
All ages (in practice, there is a iron cast division between groups for under 12 ish and groups for teens, IME, and the teens make that happen)
what kind of price would you pay?
At our group we all pay £4 per family, and that pays for hall hire. Lots of people bring along activities, and there is usually enough money in the pot to sub that when needed.
Activities/classes/structure or more geared to social?
Our group has a mix of free play plus always a craft activity, a science activity, and an active activity. Children join in with whatever they want. The activities are things that the adults want to do themselves :) Sometimes the "craft" is mass cookery. We get a visitor in about once every 2 months, to do something special and specific. There is often a theme to a week or a few weeks, but we let those emerge from the ideas that people have. The children often bring along an activity too; in fact, they often set the agenda entirely. Sometimes the active activity is a roller disco. This never gets old :)
Drop off your kids or stay with them?
Oh, stay with, definitely. It's a support thing for the parents, a way of building community for everyone, a way for children to get to know other people's parents well enough to feel comfortable going home to other people's houses in time. It means that the pressure of making it all happen does not fall on one person, but is shared by the community.