I flew through the answers so far and didn't see how much time you have for this trip, except for the 2-3 days in the north. It would be helpful to know how many nights you have on the ground to spend. Typically, considering transportation and the mechanics of checking into and out of lodging, 2 nights = 1 full day in a place.
According to Rome2rio (http://www.rome2rio.com/) there is a train from Venice to Trento that takes about 2 1/2 hours -- http://www.rome2rio.com/s/Venice/Trento. And there's a train and bus combination that can get you from Trento to Fondo in about the same amount of time. In the case of the former, you can drive it in about 2 hours, but with the latter, you can drive or take a taxi in about 50 minutes.
That seems to be the only slightly complicated part of your trip. With the towns so close, I would stay in Trento and take a day trip to Fondo. You would need to learn how to get around in each town. We use our feet, local public transportation and taxis. Both towns still might have a little snow around in June.
As for the rest of your trip, the basics are how you will get there (trains are probably the answer to that) and where you will stay (many options depending on how much you want to spend). I absolutely agree that Florence is a better choice than Milan, if you have the time. It deserves time to see and absorb, as does Rome.
According to Rome2rio, it takes about the same amount of time to get to Trento from Milan as from Venice. You could put Trento and Fondo at the beginning of your trip, fly into Milan and fly home from Rome. Because you accent the importance of this area to you, and being an immediate gratification person, I would put it at the beginning of your trip.
Where am I going with this? I recommend not taking a tour and planning this on your own.
If you can work out the northern part, which you have to do yourself anyway, you will be well prepared to do the rest of the logistics. It will be work, but not as much as you might expect. Play around with Rome2rio, use the RS book and Booking.com (http://www.booking.com/) to find places to stay and it will all start making sense to you.
You also haven't said if you already have your plane tickets. If you do, that will affect your logistics, whether they are RT or multi-city. If you don't, it may affect your pocketbook. But if you don't, you also have a chance to fly multi-city (aka open jaw) and avoid possible backtracking.
My only concern at this point is that June is only a little less than 3 months away. For the best prices, especially on train tickets, you need to get busy.
As for the tour guides, there are many kinds of English options for that, mostly for specific walking tours of cities or the Vatican or museums. Even with lots of preparation on our own, we have found that local guides make the experience better. With your logistics, you will need to make sure some of the things you want to see will be open when you are there. It is an iterative process. We decide what we want to see most and make sure that is open when we are there. The rest is much more free-form. As is so often the advice here, we plan to go back.