For context: Elf city here. I spent 5+ months in ch 5 (70% fight/30% goods hybrid). I could have happily stayed much longer, but there are a handful of things I want in ch 6-8 plus I wanted more provinces & larger quantities of resources to help my FS. So I upgraded on Christmas - leap-frogged (leaped-frog? leapt-frog?) through ch 6 & hit ch 7 a couple days ago. I plan on ambling through my way to Orcs & then staying there indefinitely. I *vastly* prefer the slow approach.
This is what worked for me in ch 5:
*Playing full Spire weekly. The individual prizes - both the ordinary ones & the premium stuff - add up & provide lots of flexibility.
*Limiting upgrades to an as-needed basis; doing most the upgrading during events for quests.
*Limiting province scouting & completing in much the same way. Also, tracking my open provinces numbers & choosing new provinces to equalize between types. The minimum to move into ch 6 is 130, which works out to 11 provinces x8 + 12 provinces x1.
*Prioritizing event buildings that produce pop & culture over regular buildings that cost pop & culture. Then select for diversity - troops production & goods production.
*City layout included "stable" & "flex" space. Stable sections = built & summoned buildings (with allowances for upgrading space where expected). Flex spaces for limited-life buildings (Goddess of Wishes, Ferris Wheel, etc) & crafted buildings (Vallorian Valor & Orc Strat Grounds) during regular play. Delete during FAs for T1s & workshops; replace afterwards. My favorite trick is to set-back stable buildings from the road by 2 spaces (using short connector spurs as needed); the 2-space frontage is flex space. Pretty much all the limited-life & crafted stuff fits there except the VVs, and then there's hardly anything to do to set up a FA street fair!
My optimal ch 5 inventory:
Basic (aka regular/built) Buildings:
*Factories - 2 each of boosted goods.
*Residences - 6 regular & 3 magic. Each magic = 2 regular, so 12 regular would be the equivalent.
*Workshops - 1 regular & 2 magic ending. 5-6 regular equivalent.
*Armories - 3
Special (non-event) Buildings:
*Pets - Brown Bear; Ice Bear; Fire Phoenix. If I'd had the chance I'd've added Ashen Phoenix. (Like most newer people, I got my Bears & Birds through the MA.)
*AWs - Golden Abyss, Needles of the Tempest, & Martial Monastery.
*5 day buildings - 1 each, alternating between Dwarven Armorer & UUs as available.
*Spire prizes - 3 Genies. 1 Trading Station if on-hand & space allowed.
*Crafted buildings - 2 Orc Strat Grounds always; +4 Orcs when not FA week. 1-2 Vallorian Valors during non-FA weeks if space allowed.
Event Buildings:
The main thing with event buildings is to *diversify*. Everyone is going to have different stuff depending on what events they've played, so I'm giving numbers.
*Evolved buildings - 4-5, mostly/fully evolved.
*Sets - Moonstone + 1 additional.
*Daily prizes - variable depending on space, production diversification, road connection needs, aesthetics, et cetera.
Overall, this set-up more than covered my needs. Full Spire & 6 rounds Tourney (9-11 provinces) weekly. 2-3 MA turnovers weekly; enough diamonds/BP to craft most Bird & Bear artifacts as they appeared. Strong FA participation. Steady growth in stockpiled instants. Plenty of troops: Produced 12-14 types. Barracks/Training Grounds troops averaged 70+ squads on-hand. Goods production: 225K average weekly increase (converting everything to T1 equivalent numbers) - that's *after* game-play & sharing with FS. No real money needed.
So, yeah, I totally understand why staying in ch 5 is appealing!