I started on multidrop for a laundry in London, ok so it wasn’t parcels, but it was still all sorts of pubs/cafe’s/restaurants/hotels. Up 3 flights of stairs, down in basements, different lifts to take, a maze of corridors, it all had to go in a specific place. And dirty collections to drag out of the same place, the bags were often stinking or soaked through with grease and scum. Started in LWB sprinters, then onto 7.5t, nothing bigger than that would get where you needed to get it, especially in the West End and ‘City of London’ square mile proper.
Up to 30 drops a day on some runs probably. The guys who kept the same runs, knew it backwards down to the minute, and some were parked up at midday after a 7am start. As a relief driver, if I was on their run for the first time, it would take me till probably gone 5pm. It is only easy if you know where you are going. Especially in a city.
As with any multidrop company, we had a fair bit of sickness, so agency drivers coming in were common. Fair play to most of them, they came and gave it a good crack, some even got the whole lot knocked out and came back the following day for more punishment.
It wasn’t unusual, though, for them to bring half of it back undelivered, if not more. I remember one guy who came to us, we got him all loaded up on the loading bay, going through the drops with him as we did it. He pulled out, parked up across the road, frantic A-Z shuffling. Pulled out again, went round the block and came back. Threw the keys and said “I can’t cope with this”. I had to feel for the guy, as I knew exactly where he was coming from.
It is massively stressful if you let it become so, and not everyone is cut out for it. I had days where I just wanted to jack it in, 30 degrees outside, London traffic, really late, and you have just missed that turning into Soho for the second time and face a long loop round again to get back to it.
It was probably some of the most valuable experience in terms of getting into somewhere tight, map reading, knowing what a certain address will look like. I.e. looking for the loading area if applicable, rather than the shop front. I’ve legged it through shopping malls before now, with bags of laundry and gone in through the customers entrances, as I haven’t had a clue that the whole complex had an underground loading area. 
Having done other things since, it wouldn’t be my first choice of work, just for blood pressure alone, but i’m glad to have an idea of what it involves.