The English sentence is unnatural. "Let us take a walk with us" is redundant.
Come take a walk with us would be more natural
I agree, that's a far better phrasing.
Or "Let's take a walk together"
this is how I would translate it
Another option: "Let's go for a walk together."
Come take a walk with us
let us take a walk ...suits me
Maybe: "Come for a walk with us" ?
Does this definitely imply that there are at least three people in the scenario, two that were going for a walk, and one more that is being asked to join?