there are lots of companies that make quick dry, light weight full length, nice looking, hiking pants. Some are lightweight and roll up nice and small, some are tougher heavier material. Some are zip off short models and some not.
Mine are full length (non zip off) lightweight but still good wearing material, dark tan colour which is great for not showing dirt, look fine walking around and are comfortable in hot weather. Made my Royal Robbins. Got them on sale a few years ago.
Used to have zip off ones, but dont really like the look and prefer a full length.
and yes, two pairs of cycling shorts are all you need.
Arrive at hotel, immediately unpack, shower, wash bike shorts, jersey and socks in shower with you, or sink (I want to get it over with)
Squeeze as much water out as possible, then roll clothes in a towel, step on it a few times, presto, mucho water out , hang in good spot and they'll be dry in morning.
If padded bike shorts arent dry in morning to your liking, put on second set and this one will dry on your bike quickly. Shirts and socks should be dry
using the towel trick is the best method of getting them nearly dry , and getting as much water out of them by hand before towel roll squish
presto, two sets are all you need.
my long pants get worn just walking around after shower, so dont really get dirty, even on long trips, so really hardly ever need to be washed.