Welcome to the forum. I would pull the plugs first and see what their condition is - they should look tan if running normal. Smoking on takeoff may mean bad valve guide seals - an easy repair that doesn't require a lot of work to achieve. The EGR valve can be pulled off and the passages cleaned out to restore its function. The oil leak could be the valve cover gasket or an o ring or seal on the distributor. Look for the sticky on what to do when you buy one of these trucks - it is loaded with information.