10er

I was given a 96 S-10 a few years ago. It came from a friend that decided, at 93 years old, it was time for him to stop driving. The truck is kind of beat up cosmetically, but he claims that it was dealer serviced at all the right times. It has only 118k on the clock, but when I got it, the radiator was leaking, and it seems to leak tranny fluid a bit. I replaced the radiator with an all Alum unit, but I'm concerned about things like a timing belt, and if it's an interference engine. How hard is it to adjust the lifters, and is it an OHC? The truck is a base model, w/out AC, has AT and is the 4 cyl engine. What should I be thinking about to maintain the drivetrain?