My toddler was 27 months old when my LO was born. I had a buggy board but found it hard work. Toddler wouldnt always stay on it & wanted to walk (I live near main roads so safety was an issue for me as he liked to wonder off). Refused to wear rains. To have a pram & run after a toddler was hard work.
So I got round this glitch by using a baby carrier & putting toddler in his buggy. It worked well in the early days but as baby got heavier it was a strain on my back, even though I had a lumbar support Baby Bjorn (second-hand from NCT sale for a fiver). Could only carry her for short periods. So it depends how far you walk etc.
So I think it depends on your toddler, how far he is capable of walking & does he wonder off/stop and look at everything as this makes your journey so much slower if you are pushed for time.
However I made do with a single pram & toddler in tow, but not walking long distances. It was a nightmare if I needed to go shopping on my own as I couldnt look at stuff & watch him at the same time, wondering off.
However its much easier now, he is 3 in July and he has a better understanding of road safety. He uses his scooter whenever we go out on foot, which makes journeys much quicker! If he gets tired on the way home, we jump on the bus.
Having said this, my friend's son stays on his buggy board (24 months when baby was born) with no trouble at all. He is lazy so getting off walking doesnt appeal to him!!!
If you go down the single pram route, make sure there is enough head room for toddler on buggy board & he has somewhere to hold onto, if it isnt a single handlebar pram.
Hope this is of help.