Originally Posted by
martianone
IMHO- contact an Orthopedic surgeon before starting your trip. He/She can advise you about your "kneeds" and schedule some postop rehab. Perhaps they might advise you to get a few gears, even the cool three speed fixed posted above would be fine. Plus the Ortho might suggest the ability to coast somewhere may be a "kneeded' pleasure along the way.
ha..
The real trouble is the 100 miles a day thing. Its doable, but in reality a fixed tour over varied terrain will need to be at a very low gearing to accommodate hills, loads, and knee health. Geared very low, however, it will be a long day of spinning to cover 100 miles/day.... I would use a dingle cog and double chainrings... and maybe even a flip flop hub with two dingle cogs, for four fixed wheel speeds. This would at least allow for climbing versus descending versus flat days.... I used to tour on fixed wheel in England, but its flat there so it makes a bit more sense...
Since the OP asked us not to chime in about whether its a good idea, I will simply say think VERY carefully about gearing, and bring some options...