2003 lexus es300 8 yr old 42k miles! what maint?

Your miles driven a week are really small. It is important to change the engine oil every 3000 miles oil and filter every 6,000 miles, if the transmission oil was not changed at 30,ooo miles I would change that and change the brake fluid every two years. Brake pads may be due in the front any where from 30 to 60 k depending on your driving habits and conditions.