My guess is the rear is a 5.00-16. The front looks to be a 19 inch wheel so the front is a 4.00-19. Maybe a 4.50. Look to be Firestones.
Tubes would be the same size as the tires. Tubes may have a metric size. A metric 5.00 is a 130. A 4.00 is a 100.
Just googled "Coker Firestone Replica Motorcycle Tires" With a bit of looking around they make a 4.00-19 for the front and a 5.00-16 for the rear.
They cost few bucks but if that's what you want go for it.
Leo