If it's any help i have twins and at the time they were born I had a three year old. I was really lucky that my 3 year old would walk where ever i took him so I bought the Mamas & Papas twin aria buggy. At first it was fine and I got through all the doors I needed to but as they get older it's soooo heavy, I can't push it anymore
I use a normal buggy and a buggy board at the moment so that I have the ease of one buggy and they can swap having a ride at the same time.