thanks TDudette -- it's a work in progress but getting clearer by the day, thanks to the input.

Belated thanks, Holly (been away for Christmas tour of friends & family in England & Wales). Not sure an owner of holiday flats would lower the rent to the long term rates we are looking for ! Would have been worth enquiring, though, but it seems the 1 bedroom flat doesn't have a balcony - and as you say, is already rented out for some of the period we'd want it. Thanks for trying to help though !

Thanks again for the helpful suggestions and other insights.

We flew into FRA, spent two nights in Munich, then took the train (daytime) to Venice, as we were looking forward to the scenery.

We stayed 5 nights in Venice and I did a three-day mosaic workshop while we were there.

Then we went to Impruneta, outside Florence, for five days, then flew to FRA, spent the night in Bacharach, and flew out of FRA the last day.

I just scored two RT FC/Biz tix on Air France/Delta with miles for March 2013 for 300k miles, so will be asking for more suggestions!