Training load is a function of duration and intensity. Assuming you kept the same intensity and increased the training duration from 50 to 200 miles per week in 2 months, IMO, that is a lot. If you increased your mileage by 10% per week, you would double your 50 miles to 110 miles in approximately 2 months. Of course, if you are riding really easy 50 miles and then increase it to 200 miles but still ride really easy, then the training will have a different affect on your body and that may be okay.
Pushing big gears for 200 miles is much harder on the muscles than spinning easy gears for 200 miles. So there are a lot of variables.
IMO, the best way is to listen to your body and rest more than you think you need. Most of gang that I run with does two to three weeks of building and then takes a rest week and embedded in the training weeks are rest days. Cross training, although it may be good for well being and overall fitness and health, adds training load and reduces the amount of cycling one can do.
Also, doing the same thing over an over again no matter how great it is, can become tedious unless one figures out ways to make it interesting. I mix it up a lot and I train at a cycling gym riding the rollers, I do group rides, I race and train at the track and I motor pace all on different bicycles. I am going on a 4 day tandem tour in May. However, the overarching variable to this mix is that I get enough recovery and rest.
Whatever you can do, or dream you can, begin it. Boldness has genius, power and magic in it. - Johann Wolfgang von Goethe, writer
Last edited by Hermes; 04-15-14 at 10:13 AM.