Good morning.
I'm planning on renting a lorry for moving out interstate (Johor -> Selangor)

however, I've got some big items to be carried along:
1 queen mattress + bed
1 small fridge (not the minibar) - W 1.8ft x H 4.8ft x D 2ft
1 small washing machine -W 1.7ft x H 3.1ft x D 1.8ft
1 kapcai motorcycle
no cabinets nor wardrobes

others will be just medium-sized containers

so, what size of lorry should I get?
3tonnes?

for ~280km journey (with tolls), how much it'll cost?
(from Lalamove, price shown was ~RM700 with a helper)

If no sofa, actually a BDM4500kg lorry (commonly known as 1-ton) is enough.

Box lorry or wooden with pagar + canvas.

That's if u pack everything nicely & utilize fully the available space lah.

yours seem very small

try google - lorry move furniture malaysia

plenty of services to choose from, not just lalamove.

1 tonne more than enough

Bigger is alwasy better, if small, u last minute upgrade, will cost you much much more.