Please help!!
 

I am taking my family on a vacation for 19 days. I have planned Some of out trip we are spending june 18-23 in london then taking the train to Paris till the 25th, We come home the July 5th, Due to my short cited decision of using airline miles we fly out of frankfurt. We have so many thoughts of what to do. Really need some advice.

1) Fly to Venice and drive venice-florence-rome then fly to frankfurt on the 2nd fly home 5th
or
2) Fly to bucharest, train to prague, train to germany end up in frankfurt for a flight home
or
3) or get a car in paris and explore Belgium, Netherlands, Germany

We are pretty good travelers. my boys will be 9 and 12.

Any advice?

First, I would spend a longer time in Paris. To spend less than two days there is really doing the city a disservice. I would plan on at least 4 days there. You mention so many choices, which other places have you always wanted to see?

In addition to asking what places do you want to see, what kind of activities does your family like to do? On previous vacations (to wherever), do you go to the mountains or the ocean, do you like to lounge and relax, or go biking and hiking? Do you like big cities, museums, a variety of foods?

My preference on our trips (with kids or without) is to have a combination of city time and country time. For example, one trip we went to London, then the Loire Valley (to visit castles), then Paris.

For your option 1, if you will be in London, then Paris until the 25 (and I also would suggest more time in Paris), you don't have a lot of time for Venice-Florence-Rome if you then plan to be in Frankfurt on the 2nd. IMHO, any of Venice, Florence or Rome deserve more time than Frankfurt does.

Just make this a trip to London, Paris, then train to Cologne and a Rhine journey from Cologne up to Mainz and then train to Frankfurt airport. Any more and you're proving that haste is waste.

How many days you give that Rhine trip will depend on what you decide when you read up on the region.

You can just take a train and look out and see lots of nice scenery and castle ruins high up, and stop for lunch at a nice town along the way. See www.bahn.de

Or you can take a boat and take your time. See www.kdrhine.com

Michel has the best solution.
Alternative: train from Paris to Luxemburg - Trier (visit!) and boat through Mosel Valley to Koblenz - Rhine - Mainz - FRA airport.

Yes Michel has a great solution. I'd modify it to stay on the Mosel valley rather than the Rhine, just because it is prettier, there is more for kids to do etc. So train to Trier and then work you way down the valley and finally up to Frankfurt.