1. Block pre-heat hose to air box
2. replace thermostat in air box

Your model has neither of these, so don't replace them.

The O2 sensor is probably fine, but replacing it wont' hurt.

In addition I would perform the following maintenance:

Replace the Oil Coller Adapter o-rings. If the o-ring at the block isn't leaking now, it will shortly.

You may want to replace the water pump now rather than waiting for it to fail at a very inoportune time.

Replace the heater control valve. These little plastic devils fail. If you are lucky, all you get is stranded. If you aren't lucky, the engine overheats and it costs you a replacement head job. I was lucky and only had to walk four miles to a phone.

Install the Coolant Loss Sensor as described by Steve Ringlee in the 700/900 FAQ.

Replace the distributor shaft seal and the large o-ring on the base. If you don't have a leak at the shaft seal I'm surprised.