My favorite small brush (and not just for travel) is a Simpson Duke 1. Mine fits nicely in a Simpson travel tube.
I travel with a shave stick (or a couple of them) and a Muhle travel synth brush. works for me
I have that Muhle on the way right now. I figured a synthetic would dry quicker.
I don't think soap size matters that much, personally. With the exception of the 8 oz tins from HTGAM and a few others, or things like the MWF ceramic bowl, a typical soap isn't that big. A tin of Mike's or B&M fits fine in my bag
Does that Muhle fold up inside its self or do you have to leave the bristles exposed?
EDIT: I see it now. Guess I should pay better attention.
...EJ 89 razor with blade ( not stopped by TSA) ...
as for soap, a palmolive shave stick is 50p at tesco/asda, that works great too and lather really easy.
Lets us know what you go for in the end.
FL Shaver what brush is that?
Yes. This one:It's a vintage Ever-Ready.
Description reads "Ever-Ready Made in U.S.A Sterilized set in rubber"
I had to pull my glasses out for that one.
I travel a lot for my job and have found that a shave stick works best for me. I travel with a Simpson Classic 2 and DR Harris Marlborough shave stick. The reason why I use a shave stick is that I find I can get a good lather regardless if the area I'm staying has hard or soft water.