How far is the hotel from the city centre and the Riverside?
20 minutes gentle walking - can be very humid. 5ish minutes by tuk tuk. Expect to pay $2-3 depending where you want to go.
Central market is within walking distance from the hotel, but elsewhere is a short tuck-tuck ride away. It is a straight and direct road to the riverside but can take a while - much easier (and quicker) by tuk-tuk (5 minutes)
It’s not that far.
5 minutes walk to the riverside, there are a few centres in Phnom Phen so hard to answer that one. Basically it’s very near the nightlife
Get an answer from G Mekong Hotel staff and past guests.