Just wondering what the general guideline is for cleaning the K&N filter that these use, normal road use... so roughly how many miles between cleans?

Also is there a disposable alternative filter that fits?

K&N claims the filter does not need to be cleaned for 50k mikes or more.
See FAQ in the www.knfilters.com site

Depends on conditons, dusty = more often obviously. I clean my Rottwieller every 7500kms (a hangover from my enduro days where you clean it each ride).