We have planned a trip to Germany the first part of April, with the help of your books. We are wondering how the Royal Wedding is going to affect our plans.
Not going to affect it at all- unless you planned on visiting a German Count or Prince who will be out of town that weekend. Other than cebratory bunting, and a one day holiday in England, the wedding will have minimal effect even on people visiting London. Westminster Abbey will be closed for a few days, and the area around the Abbey will be a traffic nightmare on "The Day"
The Royal Wedding will be at Westminster Abbey in London, England on the 29th of April, so unless you plan on being in London that day it won't effect your plans at all for Germany.
Is there something that makes you think that a wedding in London would effect you travels in Germany.
Europe is a lot bigger than you perhaps imagine and what happens in one country rarely effects travel in another unless it is transport strikes or terrorist activity. The national holiday in the UK for the royal wedding is not just limited to England but includes the rest of Britian too, so expect some disruption (minimal outside London) in Scotland, Wales and Northern Ireland too, and by this I mean that some pubs will have standing room only and there will be more drunks around.