Arcane Trickster & Ritual Caster

[JumboWheat01]

So it's soon to be time where I have to retire my favorite little halfling rogue. He's been a blast to play, so much so that I'm planning on replacing him with another lightfoot halfling rogue. What? Don't look at me like that. Anyhoo, this time, he'll handle a lot differently, being a melee-focused attacker, and, as you can tell from the title, an Arcane Trickster. I figured, what the heck, why not?

I've planned out everything so far so I can get to he stat cap with both dexterity and intelligence (for those sweet crowd-control enchantments.) That leaves me with a free feat, and I decided to fill it in with Ritual Caster, since I'm gonna have wizard spells anyway, and this can expand it with some utility and a bit of a story to the character's magical skills. I'm just not sure WHEN exactly I should grab Ritual Caster. I know the first two ASIs will be dedicated to dexterity, because he will be a rogue, and that's just common sense. Should I focus on capping intelligence first and then grabbing Ritual Caster, or sneak that in earlier?

[JeffreyGator]

You have the longest time to build up your ritual book if you do this as early as possible.

I don't think that level 4 should be out of the question.

An alternative to ritual caster (presumed wizard) is to take a level of wizard which gets you:
ritual casting (level 1 rituals only - which is about half of them)
3 more cantrips - eventually 6 level 1 spells prepped (moving all your AT spells to higher levels)

this depends on how interested you are in the capstone and leaves you another ASI to play with.

This level could be taken at any point between 2 and 5 probably.

[JumboWheat01]

Interesting idea, but I think I'd rather have access to all Wizard rituals through the feats, and I can't think of any other cantrips I want but the four I've picked out so far for Arcane Trickster (Mage Hand, Minor Illusion, Prestidigitation and Light.) Can't sneak attack with the damaging cantrips anyway, so they don't really interest me.

Still, you do have a point about taking the feat earlier. Maybe I'll do it as my level 8 ASI, push back that +2 Dex to 10 instead, then focus on INT.