Good suggestions. I’ll add a detail related to “moist wipes,” based on years of our own experience–caution, brand name coming up:

Wash’n'Dri, and specifically Wash’n'Dri, are also extremely handy as spot removers–for cleaning up that whatever that hit your shirt or tie or pants or… as you were dining. They don’t get everything, but if you squeeze them to saturate the spot and rub lightly, they do remarkably well. (My wife always carries them; we’ve saved more than one occasion on cruise ships when someone had a little oopsie at our table–including us, of course.)

They’re more expensive than most towelettes, and we certainly use other brands (to freshen up, for example), but to the best of our (incomplete) knowledge they’re the only ones that do as well at stain removal.

Since you’re likely to reach a restaurant or bar after a long sweaty walk, there’s another suggestion if you have room for it (or a purse): a small bottle of hand sanitizer (Purell or any of the house brands). Not to wipe your face or anything, but to clean your hands without access to towels. Pretty cheap at most stores, especially if you find house brands acceptable.

[As for sport coats for presentations: I'm the moderator for the LITA Top Tech Trends session, and I was planning to wear a coat & tie for that, but I'm having second thoughts, wondering whether it's worth carting/wearing even my lightest sport coat across the country. Don't be surprised if I show up shirted but uncoated.]