*I try to drag music to either Ipod, I get a circle with a line through it, preventing me from dragging music to either Ipod.*
Check your update settings. Connect your iPod and click on it's icon in the iTunes source list (the narrow pane on the left). This will bring up the preferences tabs in the main pane on the right. The first tab you'll see is Summary, look for "manually manage songs and videos", if you want to update manually make sure there is a check mark against that option, if there's not then enable it and click Apply.
*I have to manually load music to the Nanco since my library well exceeds the 4 Gb on the Nano*
Actually you don't have to use that setting, you can still add automatically if you choose the "Sync Music - Selected Playlists" option. Most people use this setting when the iPod is smaller than the iTunes library. Syncing selected playlists is just like syncing your whole library only on a smaller scale and more "selectively". When your iPod is is set to sync selected playlists it automatically picks up any changes you made to that playlist in iTunes since you last connected. Anything you added to the playlist will be added to the iPod, anything you deleted from it will be deleted from the iPod. In other words the iTunes playlist and the iPod are kept "in sync".
Open iTunes and create a playlist to update your iPod from, call it -iPod to make it the first playlist in Sources. You can make it a smart playlist that picks the songs for you or just a normal one and drag whatever content you want to have into the playlist. If you are making a smart playlist limit it to just less than the size of your iPod (for example 3700MB for a 4G iPod Nano. Now connect your iPod and when it appears in the Source list click on the iPod icon to bring up the preference tabs in the main pane. Go to the Music tab and choose Sync Music and the Selected playlists radio button. Choose the playlist you just made from the selection and click Apply. You can also sync from any existing playlists by choosing the same setting, you just need to make sure that the size of the playlists don't exceed the capacity of your iPod:
iTunes: Creating playlists of your favorite songs
How to create a Smart Playlist with iTunes
Syncing Music to iPod
How to use multiple iPods with one computer
To make a random playlist go to File>New Smart Playlist.
Uncheck "Match the following rule"
Check "Limit to" put "3700" in the number box, choose "MB" from the first list box, choose "Random" from the next list box. Check "Live Updating"
When you want to change the selection in the smart playlist just delete everything in it and it will add a new selection. When you want to change the normal playlist just delete out what you don't want and drag in a new selection.
