We will be spending one night in Alexandropolis on our way to Plovdiv, Bulgaria in early July, 2015. Does anyone have a recommendation for a place to stay? Thank you so much for the information
I assume that you'll have a car for this portion of the trip. If you're planning to take a rental car across the border, be sure to clear that with the rental agency before leaving home; often it is not allowed. There may be a bus that can get you to Plovdiv. The one daily train from Thessaloniki to Plovdiv requires two connections, via Sofia.
I tend to find Greek accommodations using a combination of Lonely Planet and just looking around upon arrival in each town. Google Maps can also help you locate hotels in advance.