Russia is designed for a religious victory (either peaceful or not), so I'd recommend taking a look at them. In short, half-priced holy sites + dance of the aurora + extra production & faith on tundra = crazy faith yields without sacrificing too much elsewhere. Similar strategies can be used for desert folklore or sacred path, but are less effective due to different civ bonuses.
Definitely agree with the strategy to get religious beliefs that strengthen/discount apostles since that's the only way to actively win a peaceful religious victory. "Holy Order" is a must to make sure apostles and missionaries stay cheap even into the late game, and get the Mosques to further improve apostles/missionaries. Good backup beliefs might be "Church Property" (+2 gold per city) followed closely by "Tithe" (+1 gold per 4 followers) because it allows some diversification and can help mitigate not building commercial hubs in your tiny expos right away (essentially each of your own cities pays for its temple). I'm really not a fan of "Pilgrimage" (+2 faith per city) unless your pantheon is rather weak because it doesn't seem to add as much value as extra gold early in the game (or late in the game if it comes to war).
Russia may be the only civ that actually benefits from "Feed the World" (food from shrines and temples). Due to its starting bias towards tundra, you probably won't be able to build farms in your expos. Since you're going to be building Lavras in all your expos anyway (especially in desolate tundra regions to get that sweet DoA adjacency bonuses), this help shrines and temples support cities without having to waste production on granaries, etc. An extra +6 food (+12 with the right policy card) hits the sweet growth spot for maintenance. I'm pretty sure that the 100% faith building policy card will also double food from the shrine and temple - can support larger cities to help get the 2nd or 3rd district online (I'd probably go commerce/harbor to maintain trade routes, campus if you're really behind in techs, theater if you're behind in culture).
To get the most out of tundra expos, its better to keep them small ~ 4 pop to minimize drain on amenities but allow for 2 districts. I'd recommend placing your expo cities in close groups of 3 in or near tundra and place the Lavras in a triangle in the middle of the cities. If surrounded by barren tundra, each will produce 7 faith from adjacency bonuses alone (+6 from tundra tiles, +1 from being next to 2 districts). If there's tundra forest nearby, even better! After building a shrine, temple, and the holy building (mosques are a fantastic choice), each of these expos will produce at least +16 faith, +6 food, +2 gold without working a single tile. This allows workers to focus on tundra hills with mines/mills/pastures/camps for production and more faith. In all, a cluster of expos at pop 4 with working tundra tiles can produce somewhere the range of 60 fpt. Not too shabby for expos cities in nearly worthless land!
In terms of wonders, I'd encourage beelining Education to get the Hagia Sophia (+1 apostle/missionary spread in that city). All of the other wonders are kinda meh in terms of religion, and the production is better suited to pumping settlers for tundra expos anyway.
Last attempt was a turn 190 RV on standard pangaea immortal difficulty, but that was before the Summer patch kinda nerfed some of the apostle promotions.
