There is no booking, but the tours start a fixed times. You can take the elevator, followed by stairs, to the roof lookout. Parking lot can be found a block away. Have a good time - we did.

move

Yes the downtown train station is walkable. The Depew station is abut 10 miles from downtown. The water in Lake Erie is in the mid 70's right now. Colder of course in the early summer and fall. There is one sand beach close to down town near the small boat harbor, but the water there is un-swimable. You need to head south of Buffalo for the best beaches or to Canada. They have the best beaches. But you'll need a passport or enhanced drivers license to enter Canada. Yes even though we are neighbors with Ontario Canada, we speak English, and so does Ontario

It's closed on the weekend

The question is, "Is this ok for 65-68 year olds?" It depends less on your age than it does your ability to climb 3 flights of stairs. Only you can assess your health level regarding climbing stairs. I would note that if you have a fear of "heights", the view might scare sensitive individuals. There is a provision for handicapped individuals to obtain access at the elevator drop off level. Since I didn't use that option, I have no additional advice. Call first to avoid being disapointed.