Warm weather means light packing! You'll be fine, as long as (1) you don't take a ton of shoes, and (2) you realize you can indeed wash things and they'll dry quickly. Take some sort of clothesline and clips, unless you know there are laundry facilities where you're going.
In addition to the roller bag, I'd take either a backpack or purse, but not both. I am a big fan of American-made bags by Tom Bihn (tombihn.com) I usually take a medium cafe bag, which has room for a water bottle, iPad, slim wallet and pouches for various things like passports.
http://www.tombihn.com/page/001/PROD/200/TB0202
I'm thinking of buying the Co-Pilot bag:
http://www.tombihn.com/page/001/PROD/500/TB0967 It's pricey but really wonderfully organized and lightweight (especially in the checked dyneema fabric). If you go to that site, look also at the packing cube shoulder bag: this one is designed to be used as a packing cube while travelling, but as a day-bag at the destination. It's really lightweight and does double duty.