I wouldn’t adjust the resource gathering, build costs, and so on, too much (if at all) on your first play through. It’s good to see the vanilla game, imho, so you are familiar with it before beginning to make alterations.
But it really does depend on your play style preferences. Some people really like the slow grind with resources, feeling like they’ve had to earn their place in the world. And some people want to have resources and levelling super quick so they can get to end-game PvP.
One thing I might consider is turning your building decay off, though. If it’s just you and a couple friends on your own private server, and you play infrequently, then you don’t want to come back 3 weeks or 3 months later and find your base gone. The decay timer prevents clutter on busy and official servers, so it has its uses. But you may want to turn it off on your own server, and only consider adding it back if you begin to notice that things are too cluttered. You can also help as you go by dismantling things you no longer wish to use (old bases, or scattered campfires and campsites that are no longer used).
With respect to day/night cycles, I like a night time that lasts long enough to make it noticeable – and to make light sources and torches and so on have some real purpose. But again, this comes down to what you’re looking for in terms of realism and immersion. There’s no right or wrong answer there.
With respect to purges, you may want to have the setting set to all three of your group being online to trigger it – at least for your very first purge ever. Once you’ve experienced one or two of these, and you have learned more about how to defend against them, then lowering the it to 2 people online, or even to 1 person being online, may be something you are comfortable with. I like the purges feature myself, but they can be unnerving if you’ve never faced one before!
Later on, once you’ve all played the game for a while – or if you decide to do new playthroughs from the beginning – then you may want to alter the XP and resource gathering rates (and thrall and pet conversion rates) to make them go by quicker. But I would try to stick with the base rates to start. Converting thralls takes a LONG time at the beginning, but there are things that help: 1) taskmaster thralls that help speed it up, 2) building more and bigger wheels of pain, and 3) catching a thrall and letting them “cook” while you’re offline. It’s slow at first, but it becomes less of an issue later on. Same thing with resource gathering, too – because the better the tools, and the better your Attribute perks are, the more resources you can gather too. It’s always important to upgrade your pick, axe, and sickle (imho) first, because those are the tools that get you your most critical building materials. To me, that’s a more satisfying way to increase your resource gathering than altering the server settings. But again, to each their own. Ultimately, it’s your game to play as you see fit.
Welcome to the forums, and have fun in the Exiled Lands!