I used to play several cities, but only 2 of them were the main ones. By the time I was in Amuni, I had dropped to only 2 cities and when I finished that chapter in both cities, I found myself pretty much ignoring one of them because it was just too much, and it was beginning to feel like a chore. While I liked the people in both cities, I had a longer history with one of them, so I dropped the one I was ignoring. The game has been much more fun since then. I did create a beta city to work on developing it. By the time I got to orcs, it too was beginning to be a drag. That city's purpose now is only to look at new features in the game.
Your question at the beginning was about parking your cities.
@Iyapo said, chapter 15 is a good place, but that one is a real slog, especially in the beginning. There are 13 techs to get you boosted T1 and 15 to get the 3 4-star troops. Of course, a lot of those techs are common. However, in both cases you will be going through the slowest part of the chapter to get there and will need some guest race goods to get there.
Since you like the tourneys, and spire, the 2 AWs from chapter 14 are fabulous! So, parking there and developing those AWs and others that will help with the parts of the game you like makes that a good place to park. You won't need RR or BP spells since you aren't moving to new chapters. The events will occasionally give a building that is better than what you have or just looks cool and you have to have it. After a while you will know exactly how to arrange your city for an FA or event. You can probably just keep 3 city plans, which you may refine a bit over time.
Another alternative is to park a couple of your cities, maybe all but one, and only do the next chapter with fewer cities. After they finish the chapter, park them and take the time to upgrade the buildings from that chapter. You can then decide if it's worth it to take your other cities through that chapter. That will give you relief from doing all 4 cities at once. You may also learn how to better progress through that chapter and you will have the experience of what it's like to have parked cities.