My favorite toy storage is IKEA’s trofast. We have 2 of them. I prefer the small bins because they are less likely to dump them but you could get a big one or 2 for big toys. You can also put big toys on the top since it is flat.
We have an unfinished basement but we put rugs down there and made it a playroom.
A lot of my DS' big trucks/construction vehicles are outside toys. He plays with them in the dirt and is super happy so that works well for us.
We don't have little people sets so I can't speak to those size wise.
Honestly with big vehicles he gets two down at a time and the rest go up high on a shelf in his closet. He can trade them out. It was too chaotic when he had access to all of them at a time. My DS is all vehicle though. We have very little of everything else. All his legos become vehicles even. They are currently Bob the Builder characters. (My H is fantastic at helping our DS with his lego creations.) So that's my life.
I line up all the Little People sets, Little People trucks and big trucks along the wall. I gave away car toys with tracks and pieces because DS is 2 and it was turning into an added chore to keep track of those and set them up for him when he didn't really care for them. I have a few boxes without covers for their smaller toys. I also have a train table where I put all this stuff when I need to vacuum. This is all happening in my family room because it's really their play room at this point and that's fine with me.
We also have a finished basement with more toys down there that are usually a mess but they are moody about playing down there. There were serious tantrums when we tried to send them to the basement last night which ended in taking everyone to bed early.