^^^Agree. I've seen 1/18 trucks running on big tracks and they look like a tiny fish lost in a huge ocean.

But it's probably more fun trying to run a 1/18 on a 1/8 track than trying to run a 1/8 on a 1/18 track.

edit: I've seen some on-road tracks that can be reconfigured - move a few barriers here and there and convert to a smaller track. It might take some planning but it can be done with an off-road track.