欸！下个星期我们一起去跑步吧。比如星期一中午，就我们俩。我家附近好像有个挺好的跑道。
That's almost a direct translation that would work just fine in Chinese.
> I though of the activity first then the time then the person. Generally that’s how I come up with how to plan activities.
Then you will be really happy to learn about the topic-comment structure in Chinese. It's exactly what you want!
EDIT:
If you really want to say "go running together" before "next week" then that's also fine:
欸！我们一起去跑步吧。比如星期一中午，就我们俩。我家附近好像有个挺好的跑道。
欸！下个星期我们一起去跑步吧。比如星期一中午，就我们俩。我家附近好像有个挺好的跑道。
That's almost a direct translation that would work just fine in Chinese.
> I though of the activity first then the time then the person. Generally that’s how I come up with how to plan activities.
Then you will be really happy to learn about the topic-comment structure in Chinese. It's exactly what you want!
EDIT:
If you really want to say "go running together" before "next week" then that's also fine:
欸！我们一起去跑步吧。比如星期一中午，就我们俩。我家附近好像有个挺好的跑道。