My first time in Quebec city during our 3000km driving trip all the way to PEI and old Quebec city is truly a gorgeous place with many architectural influences left by the British in a true European style. Most surely we will be back due to finding it so romantic and 'calm' similarly to the towns of Seville or Venice when most of the tourists are gone.
We arrived here mid September and were fortunate to have some very nice, sunny weather. We managed to find all the turns via my mobile google satellite view (as we drove from the western part of the city where they still build massively) where we also found some good parking, underneath a building off rue Saint Louis for around 22 CAD/day in a special designed multi level parking space: you cannot simply park on the cobbled streets so research this in advance and yes, parking is expensive here, just like everything else.
All is walking distance, make sure you have non slippery flat shoes or at least wedge shoes, as I tend to wear (I learned this the hard way after cutting my ankles on the cobbled streets of Santorini, however sporty I am) and plan in advance what you want to visit. Most of the indoor places of interest have an entrance fee, except the Notre Dame cathedral (Notre Dame in Montreal is around 18 CAD if I remember correctly, by contrast) and I will be writing reviews about everything worth visiting. I hope this helps in organising your day.