upgrade options

Johnyy wrote:

15-85 is almost as expensive as a 24-105 L, would the later be better?

No, see also what Shorthand wrote. L does not give a lens immediately superior image quality. L means better construction and better environmental sealing  (but usually also heavier), and the best motor (ring USM). Often the L lenses do have super image quality (usually the very expensive ones), but that does not mean other lenses do not have good image quality, and many other lenses have the high quality ring USM motor as well, e.g. the 15-85.

The 24-105 is a standard zoom for full frame (FF) cameras, and wide-open,  the image quality on FF is not so great at the borders, and it has strong vignetting at wide-angle wide open. But still, it's the standard kit lens for FF bodies, and many are happy with it.  The 15-85 is basically the very same lens, but for crop bodies (15-85 has equivalent field of view as a 24-135 lens on FF), and it has a very good reputation. So, you are better off with the 15-85 on crop, unless for very specific reasons you prefer the 24-105 focal range on crop. But for most people, the 24-105 is not the right standard lens, because you loose all the wide angle (15-24 range), which one uses for standard landscape shots. So, the 15-85 is really the lens to aim for if a larger focal range is desired than what the 18-55 can give. Another alternative is the 18-135 STM, giving longer reach at the long end, if that is something desired.

Anyway, in your particular case, make sure extra weight would not be an issue. As mentioned the 18-55 IS is a good lens, and nothing else is so small and light.