One observation I've had as a member of both very large and very small churches, along with 2 more in the middle is that big evangelical churches tend to be most focused on getting people of similar ages and stages together as Sunday School classes or small groups, with various degrees of compulsion. On the most extreme side, one local church used to and for all I know still does have a policy that as soon as someone is married, they're immediately ejected from their mandatory, high-contact singles small group and dropped into a mandatory, high-contact marrieds group, simply they're now married and don't have anything in common with their old singles group anymore. The point is that many of these big churches have a lot of different segments in them where Family 1 is involved in A, D, T, and Z, Family 2 has B, D, Q, Y, Family 3 has A, D, S, Y involvements, and Family 4 does C, D, and Q but is encouraged to be more involved.
In the small or larger but few-programs NAPARC context, there tend to be more opportunities by necessity of cross-generational and cross-stage associations, out of necessity. Where this becomes tricky is when you're the only one or two people in the congregation in that similar boat, especially if you're new and or the church is a little more reserved/standoffish. Depending on your particular context, that might mean instead of getting to know 5-6 other families all with young kids, you might be looking at befriending the 40-50 year old never married lady, a couple with some teenagers, a couple of empty nester families, a college student or two, a few single men of varying ages, some elderly folks, and maybe another family or two with kids your age or who still could have additional kids. There probably are a fair number of kids, but they might be older. You might also have blue vs. white collar differences or differences if your church attracts a lot of commuters from other areas - the more confessional the church, the more you get and farther they drive in my experience.
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Re: previous deep involvement, the number one thing I would tell you to be very cautious about is the question "why don't they have program/ministry/outreach X?" The answer may be simply lack of resources (in which case, you've volunteered yourself), it may be because it is something that does not scale down to a certain point, it may be something indifferent that some churches do and others don't, or it may be something where the church actively will NOT have XYZ program for a particular reason.
One area I do think really important for integrating into the new body is that ideally, most of the church's major activity will be centered on the Lord's Day with secondary stuff on the other days of the week. If they have an evening service, you should go in general, but this is also a very big part of what being involved in the church is when it's low-no program.
If the old church had a big worship band or full-blown orchestra, 99% of small churches would be better served by just having an organist, pianist, or just an acoustic guitar or two, but 50-60 people in a sanctuary can SING. So can 500 or 5000, but the point is that singing scales but an orchestra doesn't, especially in terms of a talent pool.
Think about it like moving from the big city to the small town or even another country. They do things differently, but that doesn't mean better or worse - just differently. If you go to Europe, you pay to use a public toilet, but here if you're polite, you go to a McDonalds or gas station and buy a drink.