When you go softmod, Downgrade to 3.2, and use starfall to block updates. Certain games sometimes want updates to play, you can get around this by installing IOS' or cIOS'. Also, you don't want to upgrade after you've downgraded as yes this would be silly.....
As for the games side of things, Use a quality dvd-r like verbatim, and when you downgrade install gamma backup loader. Note that not all games work, and some may work but still have gameplay issues or the like. Don't forget its free so you can't expect everything to work perfectly
heres some info for you
downgrading, this thread has all the files for you to install hbc, downgrade, install starfall and install gamma
also check out these 2 links, they will show you what games work with some of the softmod loaders. It will give you an idea of what works and what doesn't
Backup Launcher v3 - WikiTemp
Wii Backup Compatibility List NTSC - Wii