I have 86,000 miles on my 1993 240 Classic. What is the maintenance schedule and what should be done at this time?

Most car dealers recommend maintenance services at 30K, 60K, 90K and so on. The 30K service is mainly focused in inspection of the systems and replace of the fuel filter.
The 60K is expensive for cars with timing belt. The coolant, transmission oil and filter, and the brake fluid has to be changed. The air filter and spark plugs has to be replaced at this time too.
Most costly is the replacement of the timing belt. Volvo recommends for Volvo 240, changing the timing belt every 50,000 miles. Needless to say, they are pretty religious about this now.
The B20, B21, B23, and B230 engines are non-interference engines, meaning that the camshaft can be rotated independently of the crankshaft and no damage will result to the engine. That is, if the timing belt breaks, the valves will not hit the pistons; the engine will simply stop.
On the other hand, the B234 16-valve engines and any of the other Volvo multi valve engines are interference engines. Loss of the timing belt in these engines will result in severe or fatal engine damage.