Re-reading this, surely the seemingly insensitive mis-gendering is a genuine mistake, rather than some bizarre attempt to be offensive. Unless previously tipped-off, this is surely going to happen on occasion - and it's presumably quite a burden to a transgendered person to have to have to explain to everyone each time she happens to be wearing gender-neutral clothes or whatever. I'm sure it's also a burden to feel pressured to dress in an extra-feminine way to avoid this, but not everyone has come across this before, and is quite likely to be thrown the first time however sensitive and well-mannered they may be as a rule.
Regarding the change of plans etc, again I think some people are being a little harsh. The changed-plan was I understand changed back once the OP made the point she was a unsure of the route home. That's fair enough surely ? The organiser, perhaps naively thought a cafe shop, no more than a few miles from home in their own city wouldn't present anyone with any great difficulty - and when pointed it out that it would, went back to plan A.
All this "complain to the organisers" anger seems completely inappropriate given the "culprit" is presumably a volunteer freely contributing his time to try and help the wider community. Make suggestions for improvements by all means, but "official complaint" is a different thing.
Now, if the leader had indeed been wilfully insensitive / deliberately offensive and I've mis-read things (after all, I wasn't there), then that's a different matter, and is, I agree, utterly unacceptable.