I haven't played since before that update so can't say for sure but assuming it's the places I'm thinking of, the Caellid one is actually a bit of a bitch to get to, iirc the only way to go there is via the elevator that comes from the Deep Siofra Well. Might be a way to glitch down from normal Caellid or up the part that's near the swamps but don't know, at least the natural way you need to go through the well. That said it's not that bad you can kinda just run through, you need some keys to use the elevator but nothing bad.
For the colisseum that's in Leyndell, you just need access to that, which requires 2 bosses dead and nothing else. Can be any 2 bosses, usually it'd be Stormveil and Raya bosses but can be whatever. Also need to go to Leyndell entrance first which either requires the 2 pieces for the elevator(you can get that at lvl 1 without any fighting) or you can use the maiden "shortcut" in Raya that takes you to Volcano Manor and then walk your way out, but there's a forced boss and if you're too low it'll be quite a pain in the ass(the 2 maidens at the same time). Can also just walk up the mountain, but again there's a boss in that, the big salamander dragon thing, although this one isn't so bad if you summon the NPCs to help and have ranged attacks, even at low level. Elevator is simpler though.
I'd say both can be done at level 1 probably, lots of running and avoiding fights but doable. If you're slightly leveled it shouldn't be a problem.