TIP I strongly recommend not spending less than 3-4 days in a large city you have never been before! I made this mistake a few years ago when I did a tour of Europe and visited 13 countries in 30 days, spending only 2 nights in each place... I ended the trip exhausted and barely remembering the places I had been, I had fun but I definitely don't feel like I know anything about these countries. What if you don't have enough time? Then visit less places! I would rather spend a week enjoying just 2 cities than trying to cram in 3 or 4.
So how do you plan a trip like this?I usually plan all of my trips on googlemaps. It's a very clear map which can be zoomed and scrolled easily, you can drop markers at places you want to stop and most importantly it will tell you how long it takes to travel from one place to another!
First of all take a look at the map for the general area you plan to visit. I usually have 1 main destination in mind, so my map will usually be between that place and where I am at the moment. See if there are any other places you want to check out along that route and keep them in your mind or written on a piece of paper, also if you are returning to your point of origin I recommend making a circle and returning via a different route so you can see more places.
For a reasonably experienced hitchhiker you should be able to comfortably travel between 4-8 "googlemap hours" in one day depending on the country, so it makes sense to try and stop in places that far apart. For example: from Izmir to Istanbul takes almost 8 hours by car according to google, considering Turkey is one of the easiest countries to hitchhike and there will be a lot of cars heading to Istanbul on this route this should be extremely easy to do in a single day. So it makes sense to find a couch in Istanbul and maybe spend a day or 2 there (or of course much more if it is your first time visiting). Some hosts don't mind you just stopping at their house for one night and leaving in the morning (me for example) but couchsurfing is like sex, some people get offended if you stay only one night and leave early in the morning. So choose carefully and request very very politely if you are looking for a couch for just one night.
TIP Always carry a tent with you when ever you are hitchhiking long distances. You never know when you might run into unforeseen problems and get stuck out in the middle of nowhere. It can also be useful to camp in some bushes after it gets dark and continue hitchhiking at sunrise, you can easily cover huge distances (1000km~) by doing this. You can find cheap tents on eBay for around €15.
Once you have picked the places you want to visit it's time to start writing up a rough itinerary, either on a piece of paper or on your computer. This does not mean you can not change it as you go along on your trip. I strongly recommend you keep your mind open to any opportunities that may arise. If I'm planning a long trip I usually request all my couches while on the way around 4-6 days before I arrive to keep things as flexible as possible.
As I know Istanbul VERY WELL I decided to stop only one night at a friends house there and continue hitchhiking the next morning to Sofia. I've also visited Sofia a few times before so 1 full day and 2 nights there will be enough, and I just sent out around 5 couch requests there so hopefully should be getting a reply soon. Bucharest will be one of our main destinations which I have never been before so I allow 4 days there, I was originally planning to stop in Constanta as well but as I said I'd prefer to get to know one place than rush through 2 places, so sadly Constanta had to be dropped. After Bucharest we will hitchhike down to Varna in the morning just 3.5 google hours away to meet some friends and spend 3 nights there at a hostel which I have been told is one of the best party hostels in the world (will write about it later if it lives up to that name).
Of course this is just "the plan" and plans can always be changed, but it is still important to have them, otherwise meeting friends and being hosted by couchsurfers would be very difficult. The target budget for this trip is €110 per person, this might seem a little tight but it is better to set a target and go over by a few Euros than setting a more realistic target and still going over by a few Euros. Also of course this does not include any shopping or souvenirs that we may or may not buy on our trip.