1) polyglot's idea is sound, from having seen the fountain.
2) Don't ditch the incident meter. One of the more fun places I saw in Vegas was Old Vegas AKA Freemont. Great pedestrian traffic, terrific people watching and lots to see...you'll be able to meter incident there easily enough.
3) Don't overthink it. Portra and Ektar are both terrific films, probably will break down to what kind of speed you want...can't go wrong with 400, IMHO.