What kind and size string do i need?
12-14 strands of dacron (B-55, B-500, or B-50). Endless or flemish will work just fine. Tne string length will depend on the bow length, which should be marked.
What kind of arrows should I get for it?
Depends on your draw length, point weight, etc. You can shoot aluminum, carbon, or wood, but be sure to get them heavy enough (mass weight) to avoid damaging the bow.
Congrats on the find! I really like the old Pearson bows.
Chad