We had an amazing one locally set up by someone just like you,
All of my children went there,
Everyone who worked there were over 35 with most in there 40s and 50s, I think this made a huge difference.
Lots of messy play stations, welly walks (even in the rain) and staggered play,
when the children came in the morning, they hung their coat and bag on a peg with a photo of them on, with their name,
went into a large room with large tables with different activities, lots of activities on the floor, water fun, painting, then a tidy up time followed by fruit, water, milk, veg, toast., snacks,
Then outside to play, lots of scooters, peddle cars bikes, sand, diggers, slides, we has a slope and hill so they wizzed round, in an enclosed space, balls, buckets and spades.
all the children would go for a group walk around the woods and fields, different every day,
back inside and into the bouncy room, a massive room half filled with bouncy pads on the floor and walls, slides soft massive shapes to climb on,
the other half of the room has wendy houses, castles, forts, a massive dressing up box and rail, dolls, doll buggies,
children played, then a tidy up, followed by parachute play, dance games, sit down sing along, and then some stories,
followed by lunch,
then repeat the above.
the children started by going along with their parents a few morning a week, the Tiddles (mums and babies) as it was called, started in the soft play room, in the morning, while the big ones were in the Activity room, when the big ones had had snacks and gone out to play, the Tiddlers would go to activities and have their snack, when the big ones went for their walk, the toddlers would go to outside play, then a short walk, then into activities, when the big ones went into lunch, the tiddlers went into soft play for a last bounce , sing-song, story.
One of the staff, usually the woman who started the nursery would lead the toddler group, they had a high staff to child, it was alway over subscribed with a massive waiting list.
children mostly started doing a few mornings, or afternoons, and built it up, mine loved it, I really do think their policy of having older very experienced staff made it a very calm environment.
we also had access to a large sport hall next to the nursery, so on very wet days the outside play was in there, lots of balls ,trikes, peddle tractors, and those Scandinavian outside push long toys, some with trailers.
You need somewhere with at least two very large rooms,kitchen, loos, large hall ways, great outside space, green areas to take children out for walks.