I think that over and above the problems of organising a march is that many who have been on protests etc., do become quite cynical.
This idealised notion that by walking down a street you will suddenly persuade passersby they should rethink their ideas and think like you just doesn't happen.
However, as has been alluded to a march / rally that is as much about giving the participants a moment to really be themselves and publicly express it is different.
The IWD marches that took place in the WLM era were as much about being a celebration as a protest. And women did respond to that. Marching down Oxford Street women in offices would lean out of their windows and wave.
But also at that time although often patronising the MSM at least hinted that women were organising around their rights and equality.
That doesn't exist now. The MSM as well as SM is dominated by the TWAW agenda. And because, even subliminally the mud slinging and shouts of transphobia would mean many "apolitical" women would steer well clear. And of course it is political. We might think it is about basic rights, but those opposing gender critical views, are just as certain they are supporting basic rights.
I think currently that it is more realistically to look at building up local contacts. This could be online, but mean that should say a local council or school take a decision that undermind women's sex based rights, local women could easily agree to meet up a stage an impromptu protest or whatever. One of the most sucessful public protest by women was a rally organised in a day via the very old fashion telephone tree method ie you phone 2 women, they each phone 2 women and so on. This meant that within 24 hours of the Government say they would in future pay child benefit to the "head of the household" was reversed.
Also, given the more superficial coverage by the media small events that have a talking point ie Sisters Uncut always have flares and lots of photo ops, it would be easier for local groups where women could get to know each other to plan to do a "spontaneous" event on a saturday in a busy shopping area.