I forgot to add I have
Amex SPG - 90,000
Barclays Arrival - 50,000

This is a potential ticketing option.

From DFW to LHR end of april (1 stop, 60,000 miles + $7.5 fees)
From MXP to DFW (2 stop, 60,000 miles + $180 fees)

For return segment, is there anyway I can avoid the fees using AA miles. With the off-peak travel I am inclined to use only AA miles.

What is the best way to search for train route between LHR-PAR-LUX-ZRH-FCO?

Unfortunately there is no way around the taxes charged by European airports. ZRH would be a few dollars less but they are all at least $40 per person, none of which goes to or is charged by AA. Consider paying the fees with your Arrival card if needed and redeem points for them.

You can search rail schedules at raileurope.com but DO NOT buy there, prices are inflated. Instead check http://seat61.com/ or look up each country's respective rail website. For some routes, Ryanair, Easyjet, BA on Avios or other LCCs may be a better option.

I'm curious. What are your 2 stops here?

JFK and BNA/DCA/PIT

How about your hotels? I recall from your travel report that you had to pay out of pocket for hotel stays everywhere except Paris. In hindsight, which program would have been helpful for booking hotels?

Did you book hotels with kitchenette or at least microwave so as to save from eating outside?

Using HHonors and Marriott rewards that I already have, I can barely get 2-3 nights. If my hotel stays are going to break my bank I will postpone the trip to next year and meanwhile accumulate more hotel points.

In hindsight, I would have stayed in all the same hotels as all were chosen primarily based on location and kept us very near the places we wanted to go and see. As a result, we never used a taxi. We did use VRBO for Catania and I would definitely recommend that for anywhere you will spend 3+ nights. It cost no more than a hotel room and gave us a bedroom, a full kitchen and a much more interesting experience than a hotel full of tourists and travelers. Our only stay on points was Holiday Inn Express ZRH Airport which worked well with our schedule.

Most IHG and SPG centrally located hotels had only 2-person rooms available with points, assuming all 3 of you are 10 or older.

My 2 cents: buying VRs with your Arrival card results in a ~65% discount and you can stay where you want, so stock up on them.

The Club Carlson Visa has a signup bonus of 85000 points with a $2500 spend (which earns 5 points per dollar). The best part of this card is that it comes with a bonus feature that allows you to buy one night with points and get the second night free. You'll be able to stay at two hotels, each one for two nights, with your signup bonus and points from spending. And there are Radisson hotels in all of the cities in your plan.

There are also IHG and SPG properties but they only have 2-person rooms for award nights even though IHG will show results on a 3 or 4 person search. I would call or email about any specific hotel where you plan to stay on points.

We are 2 adults and kid is 4 yrs. From what I read, hotels are lenient about kids at that age to be accommodated within the same room as adults.

I checked using SPG points and I see availability (all of them are sheraton) with decent points at Paris, BRU, Rome and Zurich and some in London. Just not sure how far they are from major tourist spots.

We want to visit the most visited/famous destinations in each city.