The LS option only works with listing (monospace) output. PROC REPORT doesn't know anything about the page size of an ODS destination such as PDF or RTF. Generally the way to force a break is to use BREAK statement with the PAGE option to force a page break where you want it. You may want to add a NOPRINT column to the report so you can trigger a break based on the value of the column. For example, after every N rows.
Regarding "gridlines," the SPANROWS option will cause the cell that contains a single value of a GROUP or ORDER variable to span all the rows for that value.
Here's the SPANROWS doc.
http://support.sas.com/documentation/cdl/en/proc/59565/HTML/default/a002473620.htm.