Custom plugin admin page issues

The last parameter of add_submenu_page expects a function callback, not a file include – hence the error as that is not a valid callback. (See add_submenu_page in the codex.) You can include the file in the function if you prefer:

add_submenu_page( 
    "???",
    "Add / Edit Price Options in Kilometers",
    "Add / Edit Price Options in Kilometers",
    "manage_options",
    "crsc-add-kilometers",
    "add_edit_kilometers"
);

function add_edit_kilometers() {
    include( 'admin/template.add-edit-kilometers.php' ); 
}

Also, the first parameter needs to be the parent slug menu ID you are adding the submenu to for this to work, you would need to replace ??? above.