Check the age of the tires, mileage is only one component of tire life. Brakes are a definate issue on these bikes, Changing the fluid will help keep them working. My pet issue is coolant. I've got 2 1100's both with around 50k miles, both with bad water pumps. Drain and flush the antifreeze with the timing belt change. You can also replace the thermostat, and pull the waterpump cover (where the lower rad. hose connects) to check the pump. It should have very little play side to side or in / out, and only turn slightly. Like I said, this is my pet issue!!!
Congrat's on the GL1100, very nice bike, but of course I'm a little bit biased, ha!
I can tell you all the things I've done to my Dad's '81 Goldwing when he gave to me last year.
1)I took it to a licensed mechanic and him rebuild the carbs and do a thorough inspection of all systems. Also had him rebuild/refurbish the front and rear brakes. Then I drove it for a season and had a great time.
2)Right now I am in the middle of replacing the timing belts, water pump, exhaust pipes and tires. I will also be replacing all the fluids (coolant, oil, brake fluid, rear drive case oil) and greasing the final drive gears.
Do a search for 'How to' articles by GSMacLean at this site. They are the best with fantastic detail and photographs of work he has done on his GL1100.