I guess some people will find this a bit hectic but if you enjoy travelling around and using a mixture of transport options and don't mind moving around then this is a good way to visit some European cities. On this trip you will visit Prague, Krakow, Venice, Bologna, Bulgaria (Sofia) and Berlin, some amazing European cities. This trip is in September. City tax is extra as with most European destinations you need to pay this on arrival but I've found you aren't always asked to pay this, for example in Italy and in Berlin I wasn't asked to pay for it.

You also need to budget for transport to and from the airport but with options such as Uber, tram, train, taxi and bus it is best to decide what is best for you.

Flights are with budget airlines and only hand luggage is included. I'd recommend keeping packing light as I always find it helps in Europe especially when using public transport and trains as it makes it far easier to travel.

4-6 September
You'll fly from London Stansted to Prague. You'll stay for 2 nights in Prague. I've picked central hotels as I think with a limited time it is best to be central and Aparthotel David's which is near the old town.

6 September
After checking out leave your luggage at the hotel and spend a final day in Prague. In the evening you will leave Prague for your overnight train to Krakow. This arrives into Krakow early morning and I think sleeper trains in Europe are great way to arrive. Not only does it save on accommodation costs but it is a great experience. Make sure you take food and drink on the train too, for a night snack and an early breakfast.
I love overnight trains in Europe and if you need tips on train travel then this guy is amazing (link below) and can provide more info and pictures of cabins etc. I have done quite a few overnight trips and I enjoy your waking up in a new place. Some people can find the journeys a bit noisy and rocky, but take ear plus if you are a light sleeper. I'm partly deaf so I've never had a problem with any noise!
https://www.seat61.com/index-mobile.htm

7-9 September
Arriving into Krakow you'll spend 2 nights in Krakow which should be enough time to visit Auschwitz and also the salt mines as well as time to visit the castle and Jewish quarter. You'll stay at 24Guesthouse not far from the Jewish quarter and the rate includes breakfast.

9-11 September
On 9th September you'll fly to Venice. In Venice you'll stay for 2 nights at Ca' Rubino 1. Although this is a little more expensive, you get some cooking facilities and it is walking distance from sights such as the Rialto Bridge so it makes it really easy to walk to attractions. If you stay in Mestre or Lido area cheaper can be found.

11-13 September
On 11 September you'll catch the train to Bologna, one of my favourite Italian cities. There a few different trains so you can stop en route or use Bologna as a base to visit other places. In Bologna I've picked a small B&B which is near the two towers of Bologna, ideally places near the main square and walking distance to the main sights and restaurants.

13-15 September
You'll fly from Bologna to Bulgaria - Sofia. In Sofia you'll stay at the central and good rated Forum Hotel. Make sure you visit
Cathedral Saint Alexandar Nevski which is walking distance to the hotel.

15-17 September
You'll fly from Sofia to Berlin where you'll end your trip. I've picked a nice central hotel the Meininger Hotel Central Station. Again, this is centrally located but walking distance to the
Brandenburg Gate and checkpoint Charlie.

All the details:

Book flights for 2 London to Prague £53.98 on

Book 2 nights in Prague £61.19 using code AFFBOX0517 on Ebookers

Train from Prague to Krakow http://www.cd.cz/eshop the train tickets go on sale 60 days in advance and you'll need to diary in to book the train to secure your seats. The screen shot is an example of the price at 2193czk/£69.45 but it will likely be cheaper if you book in advance. This is for two sharing a double cabin. Book on http://www.cd.cz/eshop

2 nights in Krakow at 24 Guesthouse £59.97 on Ebookers code AFFBOX0517

Krakow to Venice flights 218 zloty/£43.55

2 nights in Venice £140.53 book on https://uk.hotels.com

Train Venice to Bologna book on
https://app.italiarail.com €20/£16.89

2 nights in Bologna £87.15 use code AFFBOX0517 on ebookers

Two flights from Bologna to Sofia €5.98/£5.05 book on Wizzair https://wizzair.com

2 nights in Sofia book on Ebookers using code AFFBOX0517 £52.65

Flights Sofia to Berlin €55.98/£55.27 book on Ryanair

2 nights in Berlin £110.14 book on Ebookers using code AFFBOX0517

Flights Berlin to London €69.98/£59.09

£814.91/£407.55