My Europe Trip in April

I have been trying to work out the details of my speaking trip next month, complicated by issues of how to get from point A to point B in Europe. The current fixed points are the three weekends:April 13-15 ESFL BelgradeApril 21 SofiaApril 28th OsloI have at least tentative invitations to speak in:Maastricht, NetherlandsPrague, Czech RepublicPolandBarcelonaItaly My first thought was that Maastricht was close to Oslo so I should go there a couple of days before my Oslo talk. A little online research showed me my error--distance in miles, distance in hours, and distance in dollars have only a loose relationship. It is faster and less expensive, as best I can tell, to fly between Maastricht and Warsaw, Maastricht and Barcelona, Maastricht and Rome, ...  than between Maastricht and Oslo.By my calculations, I have time for four more talks, assuming one day for travel between each pair of talks. It looks as though all of the likely locations other than Maastricht have reasonably good air connections to each other and some of them have tolerable connections to Maastricht.The next step is for anyone who wants a talk and is willing to pay my expenses–a hotel room plus air fare to their location from whichever of the other locations I end up flying from–to let me know what days would work and what city I would be flying into and out of. I can then calculate a reasonable schedule.