Any suggestions regarding Weather, Spring Bloom, etc... as to best dates to plan a trip? Mid-Apr to Mid May
The weather will be good South of the Alps anytime. It gets too hot in the summer. The earlier you go, the more money you will save and the fewer crowds to deal with. In the Spring begin at the farthest South point, i.e. Rome and work North. Watch out for Rome at Easter, the vatican will be like Mecca during Hajj(spelling?). If you can fly open-jaw, it will make better use of your time. If not, take a budget airline at the beginning or end to achieve the same result.
Depends on which part of Italy. North is too cold in April because of the elevation. We were there in May and had perfect weather visiting Milano, Venice, Rome and Cinque Terre.
Do your research on the internet; there are pages which list the average temp and rainfall by month for the major cities.