Preliminary Plans for a trip to Europe [closed]

So, due to a recent financial windfall, my plans to take about a 2 week trip to Europe have potentially moved up from "something for 2-3 years down the line" to "maybe next spring/summer". Since I haven't left North America since I was about 6, I was hoping to get some advice. I'll likely ask more specific questions as I get more of an idea, but I wanted to start by asking what are things that people recommend as part of the planning for a trip like this?

I don't really know where I want to go specifically. I know I've got friends in Portugal and England I want to visit, and a great uncle who works in Rome, but otherwise I don't really have any specific plans. Is it feasible to just kind of...go and wander and see sights, or do people recommend having at least a basic roadmap more complete than "start in England, go through Portugal, end in Rome after 2 weeks"?

How much should I be looking to budget for this? I honestly haven't traveled anywhere since I left high school, so I don't really know what hotel/hostel/motel rates run even in the US, much less in various places across Europe.

Would 2 weeks be enough for a trip like the one I mentioned above? My understanding is that moving between countries in Europe is relatively easy compared to going in and out of the US, is that true? How much of the languages of the countries I plan to go through should I learn? My European friends have said that you can generally get by on English, is that true for the most part?

Sorry this isn't the most specific question, but the eventual trip is still pretty far out and vague. I just want to put myself into a position where I can do it.