Bill,
Its not possible for the timeslips page to sort more than one timeslip per user. You could add an extra input area on the edit timeslip page (like the area for listing mods) so that your users can mention other vehicles/timeslips. It would be shown on the "details" page but not the main timeslips page.
As for the video, you could add an input box where users can post a link to a video, and then have a clickable icon on the timeslips page and vehicle profile page so that people can download it.
If you have basic knowledge of php you can get an idea of how to add extra fields to the timeslip page from the example in this post:
https://vborg.vbsupport.ru/showpost....&postcount=247
That ^ shows how to add a select box and sort by it, so you wouldn't want to actually use those exact instructions since you want an input field.. but looking at it should give you an idea of how to do it.