Building out locations pages

So i have about 450 cities which I am building into my listings website. My question is how much info do I need to put into the section of text which changes for each cities listings page. Ideally I want to add as much as possible.... but I cant have this very large text area.

My plan is to target short tail keywords in the text that is visible here then possibly add buttons which will be pop ups to large sections of text which i can hit more lsi keywords and long tail, and hoping this way it wont affect the website structure but allow me to add as much content on each page.

Most websites I look at dont even have any text on their location listings pages.

Since your competitors do not have much content, you need to research the reason of this.

For example in other industries such as US real estate listings, you can see major websites (zillow, trulia realtor) add text at the bottom of the listing such as City Guide, FAQs, average prices, etc.
I see large texts with more than 500 words at least (plus all the listings words). Keep in mind that the search term / intent and the order you display this search result in the listing content.

E.g. If users are looking for homes for sale in XCity, show that first (pics, map, etc) and later the text content such as city guide, best neighborhoods, etc.

Real estate is a very hard to rank niche, so maybe you could take it as a sample and play around for your industry.