I really need a break from work and I'm seriously considering a three week interrail trip through europe.

I have a rough draft itinerary which I think will take me about three weeks as follows (dates and destinations not set in stone)

15.06.12 UK ISTANBUL Flight
17.06.12 ISTANBUL Overnight
18.06.12 SOFIA
19.06.12 SOFIA Overnight
20.06.12 BELGRADE
21.06.12 BELGRADE Overnight
22.06.12 BUDAPEST
24.06.12 BUDAPEST MUNICH
26.06.12 MUNICH BREMEN
27.06.12 BREMEN LUBECK
28.06.12 LUBECK COPENHAGEN
30.06.12 COPENHAGEN OSLO
02.07.12 OSLO STOCKHOLM
04.07.12 STOCKHOLM UK Flight

I'm open to suggestions about places to avoid in this list or places I've missed that I could go to. I'm going for a global pass which has 10 trips in 22 days, so potentially I have one more destination via train. Have also considered ending my trip with a ferry trip to Tallin/Helsinki from Stockholm and flying back from there

Any help/advice appreciated