Flights and planning advice

Most people who are not sure of their plan or who want flexibility will just book in and out of London.
However, without committing to anything (except start and end points), a rough plan is probably a good idea.
Your timing (April to July) would mean the most logical idea is to start in the south (on the Med) and follow the warming weather (to Northern Europe and The Alps) as it rolls on to summer in July.
If Greece is on your agenda then start there, before heading to Italy, south of France, Spain + Portugal, rest of France, Belgium, Holland, Germany, Czech Rep, Hungary, Austria, Switzerland, Paris, London, UK & Ireland.
You may save paying for an extra airfare later if you commit now to starting in Athens and finishing in Dublin (or London).

You can get nice priced one-way tickets on Icelandair from Boston to many European cities. The southern most would be Barcelona or Milan. Return from the biggies like London, Paris, Amsterdam, Frankfurt, Copenhagen and others. Northern cities are cheaper, ie. $412 to Amsterdam vs $575 to Milan.

Besides, the old Icelandic Air was the backpackers mainstay.

There is such a beast as a fully refundable coach ticket but you pay a premium for it- just did a test search on Delta for a round trip to London in April and the price went from $1500 to $2200 when I specified unrestricted coach. And then even if you end up getting a refund for the second half, you still have to rebook and anything less than 2-3 weeks ahead of departure, you're assumed to be flying on Other People's Money for business purposes and fares go up accordingly.

Most restricted fare coach tickets are actually changeable but you're going to have to pay $200-$300 in change fees plus any differences in fare between old and new ticket.

IMO, the best way of handling this would be to sign up to get e-mail from a whole bunch of carriers that serve Europe, wait until they have a fare sale at a price you can live with to a major city over there, and then work the start and finish of the trip around the big transatlantic/transpacific flight.

I suggest booking a round trip ticket to Amsterdam. Then you can easily connect with another flight or train the day after arrival. This would add a night in Amsterdam to your trip, but given the length that shouldn't matter too much.

I am going to be a dissenting voice here and suggest that you book soon. Airlines typically offer seat sales in November that do cover dates for an April departure.

I would not choose London or Amsterdam return, but instead recommend that you buy a an open-jaw ticket pairing London and Milan. They are two of the best connected cities to the rest of Europe for cheap flights (including Milan-Bergamo) and Milan is an easy one to connect by train as well.

I would book the airfare at least a two-three months ahead of time. I am not aware of any refundable options that aren't very expensive, so I would either decide where I'm starting or just fly into a city with easy connections to the rest of Europe. London would be good. If you and your friend chose a starting place, then fly into there and out...somewhere on the other side of Europe. So you make your way from Athens to Dublin or London to Sicily or Barcelona to Warsaw...whatever is on your wish list. Better to move from one end of the continent to the other vs. backtracking. You could do open jaw (into Athens, out of London example), or 2 one ways. Check prices. I think open jaw will be cheaper, but I'm not sure of that.

You will need your return ticket when you arrive - immigration folks may not like to see someone entering the country without a return ticket. So you may need to show your return. Doesn't matter where the return is from (Athens won't care if you're flying from Athens or London), just that you have proof that you are leaving Europe.

I would plan a broad list of places you want to see and know their locations relative to one another on the map. Also know how far things are and a broad sense of if a train or a flight would be best. Flights and trains cost more if you book last-minute, but it can be done. Some things will be sold out same-day but a few days will rarely be an issue.

There are some sites that book up way ahead of time, so you will need to wait in long lines to maybe get tickets. There are sometimes tricks to getting last minute tickets - Rick Steves guidebooks or people on here will help with knowing how. I'm thinking of the pre-reserved tickets to the top of the Eiffel Tower and the Alhambra in Granada, but I'm sure there are plenty more.

In general, I think knowledge is the best tool to have when doing a more spontaneous trip. Then you can make choices on the fly while knowing your options. So read guidebooks and blogs, watch travel shows, look at maps, learn all you can beforehand.

You will need your return ticket when you arrive - immigration folks may not like to see someone entering the country without a return ticket. So you may need to show your return. Doesn't matter where the return is from (Athens won't care if you're flying from Athens or London), just that you have proof that you are leaving Europe.

Bit of controversy on this one. One poster reported that they were almost denied boarding at the departure airport by the airline because their return ticket was 91 days later. Only got on when they explained that since the arrival in Europe was the following day, it was actually 90 days. If you had a return ticket 3 1/2 months later, that might be a red flag. I have never been asked to show a return ticket, but they will ask you how long you intend to stay. Have a good answer ready.

I have gone to Europe for 13 of the last 14 years and have never been asked about a return ticket in Europe.
I know that whatever airlines I am flying from the US will know that I do have a return ticket. I wonder how that information is passed along to the Europeans.

Charlie, I think the airlines do a lot of the checking when you arrive at the airport, because they don't want to get stuck with you when you are denied entry at your destination - or maybe this is imposed on them by some international law or IATA regulation. When I fly from Israel to the U.S. I must exit Israel using my Israeli passport and since it doesn't have a U.S. visa, I am always required to show my U.S. passport at check-in so the airline can verify that I will be allowed to enter.

I was asked, when I landed in London, for proof that I had a ticket to leave the UK. As it happened, I was just transiting through, but changing airports to do so.

Thanks for all the advice. Much appreciated. Plan is changing and coming together a bit. Will start new post :)

Your trip will, for the latter 6/8 weeks, correspond with university holidays throughout Europe and many of these students will be travelling all summer and seeking accommodation in hostels etc, which you will need to therefore book in advance.

The best train prices here are generally booking 12 weeks ahead of the date of travel. Airfares within Europe have been available on the no-frills airlines websites for months and the prices for these flights only ever go up. These flights do not offer flexible fares. Norweigian and others offer flexible fares, but these are very expensive.

With security getting more stringent, you are increasingly likely to be asked about your return flight home and you must prove that you are not intending to stay in whichever country you first land in.