It is pretty involved, but it's doable with patience and the right tools. As for the other parts you might need to replace, you don't really know until you start the job, so you might want to be prepared to have the car out of service for as long as it would take to order the second batch of parts.

The pulleys (idler, fan bearing bracket) you can tell by spinning and wiggling with the belt off. Noisy or loose ones come out. The belt tensioner, you can tell when you take the belt off - if the pointer doesn't move as you tension/untension the device, it's probably shot. Or if the adjusting rod has hit the limit of travel. Belt - they can run for a long time in pretty terrible shape, but you might as well if it's starting to crack. Thermostat - might as well. Hoses - if they are older than about 6-8 years, or starting to show signs of age, cracks, etc., yeah. I don't know if I would replace the tensioner adjusting rod, mine is original and it has 270k miles on it and it seems to work fine.