Convertible pants — as well as shirts and pants with 18 bellowing pockets — are perfectly fine for trail wear, but are UGLY AS HELL in urban areas.
For myself, I bring only two sets of clothes with me regardless of the length of travel (my longest trip is seven months) — one set on me and one in the pack. Wash at night (5 minutes) and they are ready the next morning. I never carry dirty laundry around.
I highly recommend poly or poly/cotton blend for their quick drying, minimal wrinkling, very durable, yet very comfy qualities. Choose simple styling in neutral colors — so you can easily mix and match and have yourself 4 different outfits.
I wear these from trail to city (for all except for the most formal of occasions):
o Mountain Hardwear Canyon shirt (l/s) — or any poly/cotton blend tee shirt
o Patagonia Nomader pants
o nylon socks (black or dark brown)
o Ecco Cross suede walking shoes (black or dark brown)
To the above, just add a shell jacket (Patagonia Houdini) and an insulation jacket (MontBell down jackets depending on climate), and a compact umbrella to complete the travel wardrobe. Optional: hat and light flip flops (good for hotel and beach wear).
Finally, if hiking for multiple days where rainproofness is a must, then substitute the wind jacket with a wp/b rain jacket instead.