Wild camping, rain, water, wind - cycling touring

[jsmoke]

So if your touring with say a one man tent what are your experiences of rain, wind, sterilising water, cleaning. Haven't been camping for years and seem to remember waking up with everything inside tent soaking wet(old tent though). So are most one man tents nowadays fully waterproof or do you have to spend loads for a decent tent - any tips here? Am I right in saying you have a flysheet over the tent and then the tent itself, which is breathable I think, should you also buy a tarp, which I thinking is just like an extra flysheet? Any how about sanitising water, what's best way here, a filter, tablets, etc?