This is my travel setup for a longer trip, it might be less equipment for a shorter trip.
Brushes are all synthetic, the one in the leather pouch on the left is my old 19mm Mühle Liscio black Fibre, the one in the middle is a 26mm G5 from Arno which I only take on road trips, and the right one is a “defect” Maseto synthetic. The “brush tubes” can store a 26mm brush comfortably; I haven’t drilled any holes in them yet and might not do so anyway, since I only store dry brushes in them; if a brush is still moist it’ll go in the leather pouch which is well ventilated.
I’d bring my plastic shaving bowl and a cheap tallow soap.
On longer trips I would bring my two least expensive razors, both zamak and double open combs, if the trip is shorter I would only bring one of those.