Just seen this so I thought I'd add a few more Riverview notes as it's my main town.
Changes to make in Edit Town: The elixir, consignment, equestrian center and junkyard get placed okay but the fire station and salon usually get placed on 30x40 lots when there are still available 20x30 ones so I move those.
If you have showtime Flying V's, performance park and Micks Master Karaoke also get placed, on odd occasions the port a party warehouse has been put in instead of the salon, not sure why.
Spouse/Helpers: This has been covered slightly but there are a few people who are useful for dynasties.
As already mentioned Billy Caspian, artistic (lvl 4 painting) and nice expensive car.
Jon Lessen, many expensive cars, artistic but no skill points in painting.
The Newbies, Mags is a natural cook with lvl 5 in cooking, she is also artistic, Robert is an angler with 2 fishing points and also 2 cooking points, Bob is artistic with painting lvl 1.
The Grisby's, Yvette has level 6 cooking and level 2 gardening, Laurel is artistic but has no skill points. If you have generations signing teens like Laurel or Bob up for art club helps give them a good head start in painting and sculpting.
The McDermott's, great gardeners, both Luke and Ginny are green thumbs, Luke already has level 7 gardening, Ginny has level 6, Max and Travis are both anglers, all have fishing skill but Max is highest but only at 2 points. One thing of note both Luke and Travis can't stand art but that doesn't apply to sculpting. I know as I've used Kurt Shallow who also hates art for that before and he didn't get a bad moodlet.
Don't ignore the old folks in Riverview just because of age, they've been about a while and know a lot and will last a good two to three weeks or more on normal age setting
Rayna Kaminski, at first glance you might dismiss her as she is an elder but she is also artistic with level 3 in painting but also level 6 in cooking.
Nellie Spenster, a natural cook with level 7 cooking skill and also level 5 in gardening. Her sister Lucille has level 8 in Logic, good for tutoring those kids.
Bennie Dean, a natural cook and green thumb with level 6 cooking, level 2 fishing and level 3 gardening. In fact all three grandpas have lvl 2 fishing skill, Melvin also has lvl 4 gardening.
Norman Joy, level 5 cooking, level 3 fishing but best of all level 8 gardening, his daughter Elaine is also a natural cook and both of them are green thumbs, Elaine has 3 points in cooking, 4 in gardening and 2 in painting.
For an immortal dynasty there are many useful helpers in Riverview, especially elders to help you get started, I'm currently doing a life states dynasty in Riverview, one thing I like here is the graveyard is full, there is not a single 'remains' they all have a ghost attached to them, plus there are a couple of houses with ghosts lurking too, Remington's Ruse (Jones) and Rocker's Retreat (Lessen)
The elders can also prove useful here, befriend them before they die and they will get a tombstone, if they turned occult you now have an extra option for a future life state, old age fairy!
no omni plant at back of science center, however some residential lots do have some plants in back yard.
Deklitch there is an Omni plant behind the science center, of course if you play with pets it is not fenced in so could have been eaten. It's at the swimming pool end of the building.
Other notable locations, the mine down near Lucky Perkins spawns a lot of gems, there are some large rocks across the river from Hunter Cottoneye, a good place to find rare gems at times. Sim Henge, a little island behind the Bagley's house is a good place to find special seeds. And my favourite of all the fish hatchery, I really miss that place when I play in other towns, what you can't find there you can find up in Lost Willow Park and of course the tip of the island off the graveyard has death fish, where the no fishing sign is, robot fish are in the river behind the science building.
For insects, rainbow butterfly's spawn on the hill behind the Lin sisters, on the path that run's past the river near Hunter Cottoneye, and out by the billboard past the Joy's, I only know of one rainbow beetle spot and that is up past the Crosby's near to the hills.
I hope all this proves helpful to somebody, personally I love this town it does have it's cons in only one toddler and no pregnancies but it was made in a time when townies had babies before story progression broke, but depending on the type of Dynasty you are playing there are ways and means, just look at Trip and her breeding programs