It'll be in Munich. The geology department there is excellent and they run a summer school for researchers that I'm hoping to go to. Where did you live in Germany?
Yes, Machester apparently offers flights to...
Atlanta, Boston, Charlotte, Chicago, Las Vegas, Miami, New York, Orlando, Philadelphia, Washington in the USA and Calgary, Toronto and Vancouver in Canada. Some of them might have connections but there are direct flights to and from Chicago. It might be cheaper to travel to Heathrow, but you'd have to spend a while researching that as there are so many places you can buy flights from and the prices are almost always changing! Looks like it is possible to get the flights for about £500 if you search hard enough, though.
Nope, you don't need economics. Realistically to study earth science at Lancaster you'd only need something relating to geography or environmental science. According to the website they ask for ABB with "One science from Biology, Environmental Science, Human Biology, Chemistry, Computing, Geography, Information Technology, Mathematics, Physics or Psychology is required for entry". Essentially they want people who are at least slightly scientifically minded and ideally are comfortable with mathematics. IF you're planning on doing calculus, EVS and Geography then that's a strong set of subjects and I think it would be fine. They do seem to suggest that you contact the administration staff if you don't have UK qualifications though:
http://www.lancaster.ac.uk/lec/undergraduate/courses/earth-and-environmental-science-bsc-hons-ff68//#entrycriteriaAnd as a guideline they say they want "Pass with a CGPA of 3.3 or 3.6 plus three Advanced Placements (APs) with grades ranging from 544 to 555 in Group A subjects. SATS are accepted as supplementary evidence only." for USA students but this may vary between courses. I have no idea what that means though!
http://www.lancaster.ac.uk/study/undergraduate/international-qualifications/Open days only really happen in the summer but there's info here:
http://www.lancaster.ac.uk/study/open-days-and-campus-tours/open-days-and-booking-form/The start of April is fine, that's just before term starts so the university will be quiet and it will mostly just be research students and staff around (we don't have long holidays like undergraduates do!). So you might not get the full experience of the atmosphere. Although even if you were to visit the week after it is term time but it's also exam season so things might still be quiet. I was worried that your visit might coincide with the Easter holiday where the university is completely shut down and virtually nobody will be there except security. That happens between the 23rd and 31st of March so it's all fine.
When you get a response on your applications will vary. Some will get back to you within a few weeks and some might wait until all applications are in (the deadline is middle of January) before considering who to interview. Interview days are happening over the next few weeks in the environment centre and most people get responses a day or two after the interview. Then you place is confirmed whenever your results come through. In the UK this is the middle of August, but I imagine it will be different for you.
I think our system seems a bit fairer than the US system. I had a friend in SC who really struggled to pay the administration fees for every university he applied to.
Sorry for rambling on - it's more interesting than doing actual work