I've done the same and skipped the neutral week of the pill on a number of different occasions and it worked fine for me - although I have to say I didn't feel great, sore boobs and felt quite bloated during the extra week. (Don't use oral contraception any more. Don't like all the chemicals )

I'd also recommend the Keeper or Diva cup and would echo what someone else said about getting it NOW and practising a few times. I've been using the Keeper for over 3 years and the only time I leaked was after leaving it too long when I knew I should have emptied it.

Having said that, as long as you've got dark shorts you can probably get away with a small amount of leak. If you rinse your shorts in cold water as soon as you shower/change they normally come clean pretty well.

As for knickers - have you ridden 'au natural' before? If not, why not give it a try - it's a lot more comfortable and you don't have any bunching or chafing - not to mention wear and tear. Padded shorts are made to take some punishment, but not knickers which I find can get messed up with chamois cream, sweat etc.

Hope this helped.