What I found worked best was neither of the above options -I simply used a trolley! When Alex was a newborn I could transfer him straight from the car to the trolley via the capsule and even use the layback seats they provide covered with a blankie of course. When he was old enough to sit up I would put him in the trolley sitting in a Trolley monster cover.

This worked really well as I didnt have to purchase a double pram or stroller and Gaby could sit in the base of the trolley or sometimes stand on the end (not the safest I know but we never had an issue ). She was 2 1/2 when Alex was born and would still get tired sometimes when we were out at the shops.

Obviously this wont work when you are out somewhere other then a shopping district but it may give you some food for thought - eg have a really good think about where you go on average and how often would you actually need to put Lucas and or baby in a pram/stroller.