Bill,
get some travel books and readup on whats there and how to get around.
getting there is half the battle, the rest is in the details.
You can use a travel agent, but with google at your finger tips, why? also, that travel agent will require some $$$ for their services. You can make your family help with this trip by doing some of their own homework and figure out what to do/see in the places you want to go. after all do you want willing participants or reluctant passengers? I find that doing the work myself gets me in the mindset to go and i know alot of the info once i get there. Of course if you just want someone to do all the work and you follow the planned itinerary, there is that too.
What you can do is to just assume you will spend 2 or 3 full days (or nights) in each city and see how the total works out. You dont even know the travel times between places, but you will get an idea if you eyes are bigger than your days away. Also realize you will loose one day traveling to there.
just some hints.
When planning a trip, try to plan some type of path. Either circular or some linear path. It keeps you from criss-crossing your path or back tracking since both can be time consuming and expensive. Use google maps to print out areas and start marking up the maps with places/areas you want to see. that will show you where you want to go and if you can find some path to use. Sometimes it will show you just to plop down somewhere and do day trips from a central location.
You can also go to a store to get a laminated map and be able to mark and wipe off what you dont like.
Google is your friend. along with travel books, friends and boards like this. I say, if you dont know whats there, you really cant plan or do it.
Trains. look at seat61.com. This guy puts in alot of homework so you dont have to. Trains are waaay better in Eruope than the USA. What i like about them is that they go from City Center to City Center. No having to deal with, "how do i get from the airport into town" BS. also, there isnt any, "please turn off all electronic devices...blah blah blah". One other thing is that a trains 2nd class seat is like a planes 1st class - at least that has been my experience so far. alot more room and you can wonder around without having to worry if the "fasten seatbelt" sign is on.
good luck with your trip and happy trails.