If you really want to enjoy your retirement, lay some track in your garden and get a LGB 2-10-2T with sound. Watch and listen to it running at dusk, its awesome.
I first went to the Harz in the late 1980's, what a place. I've still got the sound cine film I took there. Been there several times since, one year my wife and I camped at Schierke and spent an afternoon riding up the Brocken with our bikes in the brake van, then cycling down, did it several times much to the amusement of the HSB staff. Had a footplate ride too.