In terms of how much each is "worth," you need to look at two things, how much currency each 2hu has, and how much they're worth in assets.
The problem with looking at currencies is that we're rarely given a solid measure for how much each is given. We don't know how many donations the Moriya shrine gets verses how much Marisa makes from her shop. However, by the very nature of her job, we can assume this would be Komachi, who has so much money that she literally throws it at you in some of her danmaku.
In terms of assets, then, this one is debatable. Not counting the Lunarians, the Big Four, or Yukari due to being indeterminable, I'd say that it's either going to be Satori, Remilia, or Byakuren, in that order.
Starting from the lowest of the three, Byakuren's assets are comparable to the Moriya shrine, except in a tradeoff for steady donations and the good real estate, her temple transforms into an airship, which would make it worth a fuckload more, contains the Hall of Dreams, and any treasure that Shou and
Nazrin gathered. For a bhuddist without any currency, she sure has a lot, including the only motorcycle in Gensokyo we know of.
Remilia owns a similarly-sized estate, which would put her as the bottom if not for one thing: she has a fuckload of employed fairies and youkai, which signals that she's getting a consistent stream of wealth from somewhere, and given how her power can be exploited for doing something such as "fating" a meteor, she's likely never to be fated as anything less than upper-class.
With that being said, both of those arguments pale in comparison to the assets under Satori's watch. Satori is the master of the Palace of Earth Spirits, and by extension of Former Hell, the only master for it we've seen. If you really want to compare it to the other landmarks, the Palace of Earth Spirits isn't too bad of real estate either; the temperature is as comfortable as you want to make it year-round, it's near a city with plenty to do downtown, and it's near some scenic hot springs. Unlike Hecatia, she doesn't necessarily need to share all of this control with anyone, and unlike Shiki she doesn't need to lose anything she gains in terms of spirits under her control. Despite Hell "filling up," Orin's backstory hints that she presently enjoys her job because she can communicate with the Earth Spirits, hinting that the amount of underlings under Satori is continually increasing similarly to Hecatia, except they're more willing to obey her. You could take all of that away, and Satori would still be in the top 5 because of one other huge asset she possesses: Gensokyo's sole source of nuclear fusion, which we know has been used by other youkai under Satori's watch, as was the purpose for giving Utsuho partial divinity. To recap then, Satori's assets compose of good real estate, Gensokyo's most powerful source of energy, and an immeasurable number of spirits under her control.
So, yeah, go after the wealthiest. Go rob either the Grim Reaper or the mind reader.