Playmobil for 4 year old

[Pips45]

Hi, my nephew is finally visiting us this summer now it seems safe to fly. So I'm thinking of getting some toys from eBay for while he's here.

Playmobil toys look good and a lot of the auction items seem very cheap, which is great given they're only needed for 3 weeks. Can anyone suggest the best Playmobil sets for a 4 year old boy please?

Camper van or treehouse. Still played with years later.

My son likes the bin lorry, tractor with trailer. Any vehicle basically. We get it all from eBay
Are there any smaller children that will be around? Some of the small parts are very tiny

Thank you, they all sound brilliant suggestions and I've definitely seen relevant things listed.

Luckily we don't have younger children around but that's part of my worry, I don't want him getting bored.