Athens - Florina: As far as I know, there are three daily trains between Thessaloniki and Florina and 5 trains from Thessaloniki to Athens.Correct me if I'm wrong

Florina - Bitola: There are currently no trains and I don't think that there will be train service in the near future. If you have luck, there will return the Hellas-Express from Belgrade and Skopje to Thessaloniki, but before summer I don't think that it will return. But you can take a Taxi, there are only 30 minutes by car.

Kochani - Sofia: There is no train line, but I recommend to take a train from sofia to kulata. From there you can take a bus or taxi to Strymonas. From there are (as far as I know) two daily trains to Thessaloniki. If you take this route, you have also no problem to cross the Florina - Bitola border

@Florine Srt 

As @mcadv  said :/

Currently there is no International train out from Greece :/
Usually Thessaloniki - Bus replacement - Greek Border change to Train - Skopje - Nis - Belgrade
or
Thessaloniki - Strymon - Bus Replacement - Kulata back on train - Sofia
as suggest above you still can cross the border by Taxi or ofcourse use Buses to travel arround :)

and there is no Route from North Macedonia to Bulgaria (they wanna build one but till yet not much happend :/)

B smart and forget trains for there. Instead of these cumbersome-train/taxi or bus/train again, with maybe just 2 or 3 trains/day, do not even think about a pass, buy ticket when needed for what suits you best. A direct bus may run much more often and be in half the time of that cumbersome combo.

And even when in BG the problems do not stop: connections from there into Serbije also suspended, to ROmania just 1/day via roundabout route and coming spring one of the main borders from RO to HU is also closed due to works.

Other as promised on the site there are NO free ferries for now It-GR, you have to pay ticket anyway, get discount as ju/se-nior

@mcadv thanks, I know, that there is no trains crossing the borders, that’s why I wrote this message… Do you know what are the busses companies crossing the borders from Greece ? And do you have any idea of the price of these journeys ? 

Regarding the ferries, the discounts with the pass are actually still very interesting: 10 euros instead of 60 to go from IT to GR with superfast - anek. 

Thanks for your help :)

@Womble and @seewulf thanks a lot for your help any idea of the prices of the taxi to cross the border ? Did you take this route yourselves ? 

I did this route back in the good days with trains There are several post´s on tripadvisor about the taxi. However i prefer currently a direct Bus from Sofia to Thessaloniki (less stress as with Train - Taxi - Train connection)