I took it in 2022 before they changed the itinerary a bit.
Venice - yes, the bridges in Venice have steps not ramps so you have to carry your suitcase over.
Monterosso al Mare - I've stayed here 3 times and each guide has done it differently. Last time it was pouring rain and the hotel sent a small pick up truck to collect the luggage while we walked from the Monterosso train. The bus parks at the Levanto train station so you do have to get your bag on the train and off again in Monterosso. Going back it was pouring again and we walked with suitcases to the train station. Other times I've walked. The whole route is paved, not cobblestones so it's not bad.
Castelrotto - Some tours stay here some stay in other locations. Here, the hotel was in a pedestrian area so we had to walk a block, go up a flight of stairs and then on to the hotel.
Rome, the bus had to stop a few blocks away. Had to roll over the broken pavement and dog poo of a typical Rome sidewalk. And yes, I wiped the wheels down when I got to the hotel, lol.
Siena, Florence and the agritourismo the bus could get either in front or fairly close. Am I forgetting a stop?
I used a 2 wheeler Osprey Ozone as I was flying one leg on Air France and worried that I would not meet their dimension and weight restrictions. I did not have any problem with rolling mine but it was light enough that I can lift it up for a flight or 2 of stairs.