Thank you all for the advice.
Plan is to fly into FRA at 0530 (hopefully we can get SOME sleep on the "near flat" business class seats of the Luft AB 0330), store the bags at the train station, take the ICE to Cologne, return that night, pick up the bags and check into the IBIS FRA Airport (only 39 Euro! - why use 35K HH points).
Next morning we are off to Rome at 0730. I will be asking some Rome/Venice questions on that board in a few.
thanks again -- I never knew how great this Forum was! Been reading it for years, and JUST signed up.